Fun deck - I like my slivers chunky! Some quick thoughts/suggestions:

• What's your win-con if someone has something like a Crawlspace or Norn's Annex out? Ashnod's Altar + Sliver Queen already gives you infinite ETBs and LTBs, maybe add Impact Tremors/Bastion of Remembrance/etc as an alternative win-con :)
• It might be worth adding Phyrexian Altar alongside your Ashnod's Altar
• Anointed Procession gives you twice as many slivers to work with, meaning the ETB/LTB works with Phyrexian Altar as well as Ashnod's Altar - as well as many other cards
• Be very careful with Harmonic Sliver and infinite slivers - it's not a 'may'! It's fine if you stack your triggers so all of your slivers destroy the same artifact/enchantment, otherwise you might be forced to destroy your own stuff. (Alternatively, you could go super-mean and add a copy of Enchanted Evening alongside Harmonic Sliver to destroy all of your opponents permanents...)
• If you decide that you'd rather go down the non-infinite route, Vanquisher's Banner is a great card to make sure you're always drawing more gas! Cycling lands would also help that draw issue.
• Speaking of - the new triome cycle that is coming up in Ikoria (e.g Indatha Triome) will fit very nicely in your deck! They've also got all of the land types so can be fetched by more types of fetchland - not that you've got those in the deck :)
• Mind if I ask why Hive Stirrings is in the deck?
• FYI Quicksilver Amulet does the same as Belbe's Portal in this deck - though it costs more mana after the first activation :) Since you have Sliver Queen as your preferred 5-drop, it might be worth swapping the artifacts so that you have a 4-drop 'instant summoner' instead of a 5-drop. It also gives you plays even if you're stuck on 4 lands.
• I'm glad you haven't added Cathars' Crusade! It's a very powerful card for this type of deck, but I'll be the first to tell you that it's incredibly painful trying to keep track of all the +1/+1 counters.

You mentioned being unsure about the number of lands/mana rocks - most people operate on a '40 lands minus (number of rocks)/3' basis. Since you've got 7 forms of mana (I'm not counting Gilded Lotus since the top of your curve is 5 mana) this means 38 lands is probably about right. I've got a Narset deck with 36 lands, but that has 14 mana rocks! (Speaking of, Coalition Relic is a really great mana rock, especially when you need different colours of mana.)

(If you're really wanting to optimise your mana base, then it's worth thinking when you're likely to play certain cards. [T1->land, T2->land+rock] means that you'll have 4 mana to play with on T3 instead of the usual 3. If you have loads of 2CMC rocks then that means you'll probably want to have more 4CMC spells instead of 3CMC spells - but I don't think that level of mana optimisation is something you need to worry about in this deck or in casual EDH!)

I notice that you've not got any land-ramp in the deck even though you have green available. I'd really encourage you to add some cards like Cultivate and Kodama's Reach, since they also act like card draw as well as ramp, and mean you're much more likely to hit your 5 lands on T5. Also, people are much less likely to steal or destroy your lands than your artifacts, and using land-based ramp means you're in a much better situation to catch back up if someone Cyclonic Rifts the battlefield.

Hope that's given you some food for thought. Let me know if you want me to clarify any of the above!

One last thought - you don't have much in the deck that protects Sliver Queen. It might be worth adding a Crystalline Sliver or similar (e.g. Swiftfoot Boots or Lightning Greaves), though that would also mean you are no longer able to target any of your other slivers with Crypt Sliver or similar effects.

Also, I've just spotted that Lavabelly Sliver functions as an infinite ETB/LTB win-con. My bad for missing it earlier!

(I've actually done two Sliver-tribal decks of my own if you'd like some ideas - Alesha, Who Smiles at Slivers and Xenagos, the Sliver Party. One's for Tiny Leader and the other's for Oathbreaker, so they're built for very different design-spaces than and EDH Sliver Queen allows/requires. I've also not followed my own advice in the Xenagos deck about land-based ramp, but that's because I wanted all of the ramp in that deck to be sliver-based!)

Hey there! Thank you so much for your feedback Fun fact: not so long ago you wrote such a good comment like this on my friends angel tribal deck mono white indestructeble plays . I was green with envy over the awesome feedback he got, you wouldnt believe my face when i saw your name in my inbox :D

I have noticed the new lands coming in Ikoria and you bet i am excited for'em!!!

Here are some notes on why i have speccific cards and why not. Harmonic sliver: I got in in a mystery booster in foil and thought it would be nice to have in there Belbe's portal: I also got this one in a mystery booster and thought i'd keep it in a sideboard if i ever wanted to get it Quicksilver portal also look very nice if i can get it :) Hive stirrings: I put it in mostly because i thought it could help me out early and i also thought: Hey, look at that! A sliver sorcery!

The reason i havent used green for any mana ramp is simply because i dont know if i would need it yet. I have never played a deck with this many mana rocks and lands and i have never played a 5 colored deck either. I thought that with so many lands and so many mana rocks i might survive.

My friend has a sliver deck that tries to do it all at the same time, that is why i've limited my slivers to slightly offensive ones and those who help me go infinite or work with the infinity combo, excluding Sliver Hivelord, who is there for the lolz. I intentionally chose not to include The First Sliver and Sliver Overlord.

Cards that i use for the infinity combo or that benefits from it: Use for infity : Basal Sliver, Mana Echoes, Intruder Alarm Benefit for infinity: Darkheart Sliver, Dormant Sliver, Lavabelly Sliver, Necrotic Sliver, Descendants' Path

What i might change when it comes to giving my commander more resiliance or possibly adding Swiftfoot Boots or Lightning Greaves i dont think that's a bad idea at all. If i remove Hive Stirrings and possibly another of the guild mana rocks i could get in Coalition Relic

If you were me, what would you remove in favor of what you've said earlier?

and also, im not so worried about Cyclonic Rift no one in our playgroup can afford it. I know this comes a little late but this deck is supposed to be my "High budgett deck". We usually dont play with so expensive decks in my playgroup, but i wanted to make one regardless, i will no doubt get to play it regardless. at our LGS or in the playgroup :)

Once again, thank you so much for the time you've spent to give me feedback. I appreciate it so very much. Stay Safe!

TCK_Green sorry for tagging you, just thought i'd do it so you'd see my reply. Have a pleasent evening.

Hey - sorry for the super-slow reply, thought I'd done so a month ago but just seen that I failed to!

No problem :) I'm glad my feedback has been helpful. I'm very much a casual brewer, but I like seeing decks where people are very much wanting to have fun!

Thanks for confirming about the infinite-ness. Agreed, you probably have enough infinite payoffs already - I wish I could use the 'I was tired' excuse about some of those payoffs, but I can't remember when I wrote my feedback and according to the TappedOut timestamp it was mid-morning...

Removals

Agreed that the Lightning Greaves and Coalition Relic were good additions. I'd probably think about also removing Amulet of Vigor (I'll be generous and say that you have 9 cards that would currently benefit from this - assuming that you don't add loads of Ikoria lands!) and Intruder Alarm (you only have 4 Slivers that benefit from infinite untaps, and by the time you have infinite creatures you probably don't need those. Plus, if you have one of the Slivers that gives Haste out, then you you'll have the equivalent of Intruder Alarm with all your infinite Slivers.) Then again, it's a fun win-more card so there's no harm in keeping it :)

On a related note - how many cards are you expecting to draw? I only see 3 sources of card draw in the deck (Dormant Sliver, Distant Melody, Patriarch's Bidding) - you're going to have an empty hand much more often than not. You've got ways of using your mana in your sliver abilities, so that's not a concern, but Reliquary Tower's ability is useless for you. I really think it's overplayed in EDH because people see it as bonus value. In your deck it's a fairly unhelpful land to have in your opening hand - you really want lands that tap for coloured mana. I'd much rather have any of the (e.g. Vivid Grove) then Reliquary Tower for the colour fixing the provide, even though they enter tapped. Speaking of, it might be worth adding a couple of those in - though at some point you might prefer to add more Tap Tri-lands instead (e.g. Ikoria lands). Your call - but beware of putting too many tap-lands in the deck, you'll be surprised how much it slows you down and puts you behind everyone else :) (and yes, I do think land-ramping is often better than having mana rocks - people don't feel bad destroying artifacts, but it's an unwritten Commander rule that lands are semi-sacred!)

Why have a card

It might be helpful to think how happy you'll be to draw a certain card from the top of the library in the early/mid/late game. For example, whilst Amulet of Vigor is fairly nice to have in the early game, it's a fairly miserable draw in the mid/late game since you have nothing that would really benefit from it - which is why I'd take it out if it was me. That's just my two cents of course :) another way people tend to valuate cards is the - 'how helpful is this at (1) the beginning of a game, (2) if we're all roughly equal, (3) if I'm ahead and (4) if I'm behind'. It's one of the reasons I put a lot more interaction in my decks now than when I first started brewing, since it's usually pretty decent to have in (2-4) :)

Other thoughts

I notice that you've got some Slivers in your maybeboard twice. I did also spot the Ikoria card, which got me thinking (and I honestly don't know the answer to this) - do Slivers count as having activated abilities, and if so then how much would you need to change to make the deck super spicy and have Zirda, the Dawnwaker as a companion? On that note, Training Grounds would be a decent addition to this deck. It's a strict upgrade to Heartstone in this deck - but I say have them both, you'll almost always be happy to pull one of them off of the top of the deck! :)

The 'card draw' comment earlier got me thinking. Have you thought about adding Guardian Project? Since 1/3rd of your cards are non-token unique creatures, it means you'll be drawing a card on ~1/3 spells. It's not the best of cards to pull off the top, but if you get it down before you finish emptying your hand then it can give a bit more gas to push further.

Final thought - it might be worth adding a couple of instead of signets. It means you can split your mana more easily, and depending on the format and how quickly you expect to win, you probably won't mind the loss of health. It's one of the reasons why Shock Lands are so expensive - taking 2 damage is an easy trade if it allows you to fix for the cost of life!

As before, it looks like a fun and fairly rounded out deck. I've done 2-colour and 3-colour Slivers, but I haven't done 5-colour yet because there's a lot of ways I could take it; I think I'd probably end up with a similar deck to yours, but with fewer creatures and more ramp so that I can get my Queen out on T4. Let me know how it goes and what other changes you decide to make over time. I'm going to go away and ask some questions about Zirda - if so, then I definitely know what Sliver deck I'll be building!

GL, HF, and stay safe! ^_^

Hmm. Apparently TappedOut didn't want to display my hyperlinks properly. I must have done something wrong when submitting!

'Removals' paragraph 2: ... I'd much rather have any of the Vivid lands (https://www.mtglands.com/main-vividlands.html) (e.g. Vivid Grove)...

'Why have a card' paragraph 1: Another way people tend to valuate cards is the quadrant theory (https://magic.wizards.com/en/articles/archive/li/quadrant-theory-2014-08-20)

'Other thoughts' paragraph 3: Final thought - it might be worth adding a couple of Talismans (https://scryfall.com/search?q=talisman+of) instead of signets.

Was looking through the upcoming C20 cards and spotted Species Specialist - thought it might be a good way of turning Sliver sacrifices into card draw in your deck! Also noticed that you're not running Skullclamp - any reason for that? It's largely viewed as very OP in any deck that can generate 1/1 tokens; 1 mana to draw 2 cards is an unheard of rate in Magic. Both of those would be good ways of digging for your combo pieces if you've got Sliver Queen out on T4/5 but haven't got any of your infinite payoffs yet - but again, they're just suggestions :)

TCK_Green you are a true saint! If only you knew how happy i get when i see i've gotten another comment from you! Thank you so much for taking time out of your day to comment!

Anyhow. As per your advice i will try and remove the Amulet of Vigor, Intruder Alarm and Reliquary Tower. The main reseason these three were in the deck to begin with was because i got them from mystery booster packs and thought: Hey look! Free value!

AS of right now i have changed a couple of the lands and i think for now this is as much as i'll change. I have ordered the deck two weeks ago and i'm still waiting for it. I did add Guardian Project Once it arrives i'll figure out if it needs more card draw, but right now. In terms of card draw im keeping it where it's at. as for the lands i have changed i put in: Submerged Boneyard, Vivid Grove, Stone Quarry, Highland Lake, Temple Garden, Godless Shrine, Overgrown Tomb and Hallowed Fountain

in the process of making this comment i saw you made another comment! I have now also added Skullclamp, how i did not think of that in a deck like this is beyond me! Thanks alot

if i do end up needing more card draw i will be sure to keep posting updates to the deck to notify you.

Once again thank you so much for your time! Stay safe, friend!

Forgot to mention, the reason im not running Training Grounds was primarily because of it's price. Though if i ever do add it i'll tell you ;)