So, I wanted to build Affinity, but I wasn't sold on the Sneaky Snacker Spellstutter Sprite plan. It does seem good, but if I wanted to play Faeries I'd play Faeries. I want to flood the board with tiny pieces of crap, then drop cheap/free threats. I'll admit that this is probably suboptimal, but there are advantages to this approach.
The deck is Rakdos. You need more black artifact lands, so I'm running Mistvault Bridge, the best bridge in this shell since it bluffs the blue people will already be expecting. However, I don't actually want to run Thoughtcast. Fanatical Offering alongside Experimental Synthesizer or Ichor Wellspring is better than Thoughtcast in every way, and all of these cards alone are comparable, and give us a card selection engine, and I don't even maximize Offering. 3 is all I need, you need to see threats and answers more than card advantage. My initial impression was to run the blue for Cryogen Relic, but this taxes the mana a lot. Hydroblast, while good, is not my preferred approach to the red matchups, and the other blue cards are marginal, besides Thoughtcast, which is unnecessary and also means running too many durdle engines for my taste. I want to drop threats!
The Mana
We're running 12 black artifact lands, 9 Red artifact lands, 4 of which overlap, and of them 9 are taplands. That hits good numbers - think of it as a black deck with a big red splash, and these numbers look okay. We're also on 2 Lotus Petal. This was a 4 of, but I found you needed that first land more often, and so I cut it to 2. It's basically 2 mana in the deck, and allows for broken starts, and I'm treating it as half a land. In addition to these 19 cards, I'm running 2 Navigator's Compass. 3 life can swing an aggro matchup your way, it's a small artifact that enables our artifact payoffs, and it serves as a sort of Arcum's Astrolabe for the purposes of fixing mana, meaning if we see the wrong quarter of our mana base we might still be able to cast our other spells. Note that this plan does force you to mulligan for mana purposes often, which means you also just have to keep any hand with lands and spells, but I can live with this. That's how I live baybee.
The Enablers
4 Blood Fountain is the purest of our enablers. The Blood tokens do get cracked in this deck to mitigate flood after a Fanatical Offering or two. Also, recurring 2 bigish threats for 4 mana is awesome in the late game. However, this card is mostly just a 2-for-1 on dorky artifacts, just little shits you poop onto the battlefield. With this and your 2 land drops you already have 4 affinity, and metalcraft.
Experimental Synthesizer is a potential 3-for-1 before we even get to Fanatical Offering, and is an incredible combo with the offering. Ichor Wellspring is much weaker, but does the job and is much easier to cast.
Welding Jar is a free artifact. Nuff said. No, I mean, this is defensive magic, and useful in combat. While you will side it out when the exile effects come in, it seems downright broken in game 1. And just being a free artifact that counts for affinity and taps for improvise is good enough anyways.
2 Nihil Spellbomb are run main. Exiling graveyards is a necessary effect in some matchups, and here where it's a durdley artifact that cantrips, sometimes even when sacrificed for Fanatical Offering, so even when it's dead it works as an enabler. That's something I'm always looking for in a deck, ways to fit sideboard tech cards into my engine, and this does that.
The Threats
We've got 12 main threats in the deck, 3 full playsets. Refurbished Familiar is pretty incredible. It's not quite a flying Frogmite stat wise, but a 2/1 flyer for one in the extreme early game is good, and forcing the opponent to discard is obviously good value. If you somehow catch your opponent empty handed, it even draws you a card, and this is an insane rate for that effect. Myr Enforcer is less impressive ability wise, being just a big guy. However, 0 mana 4/4s are pretty friggen dece tbh. Most of the bigger creatures in the format are 3 toughness, and while there are a few things that this can't tango with, it is good to just get down a big old guy. Glaze Fiend is the last card I'm trying in this slot. It dodges Krark-Clan Shaman, and grows out of hand if dropped early. The previous threat was a nonbo with Krark-Clan Shaman, while this is an asset to it.
We also have 1 sorta "game ender". Makeshift Munitions is a staple in artifact (and sacrifice) decks of all kinds, and for good reason. It's a flexible, repeatable way to sacrifice Experimental Synth that also threatens to close out a game.
Removal
Glavanic Blast is all that makes the cut for removal, and it's all we need. It should almost always be 1 mana for 4 damage, which is a great rate. A couple of these can help close out a game, and then the rest of the time it's efficient removal. Krark-Clan Shaman gives us a maindeck creature sweeper that's also a payoff for our Wellsprings and Synthesizers and Blood Fountains etc. After testing some, I decided to main 2 even though it's occasionally dead or symmetrical, because it's the best remaining sac outlet when it's good, and it's usually live.
The Sideboard
You'll usually be siding out all 3 Welding Jar in game 2/3. In addition, you may want to side out Nihil Spellbomb if they're not a graveyard deck. Against Sneks you'll want to side out some number of Galvanic Blast as well. You don't ever side out Navigator's Compass even if the matchup doesn't need life gain, because it's part of your mana plan.
1 Krark-Clan Shaman is in the side for creature matchups of all kinds. This card is worse in this version than the Faeries version, but mostly you want it against go-wide strategies that don't rely on you destroying your own Myr Enforcer.
Suplex makes the cut over Cast into the Fire. Creature sweepers are already covered by the shaman, and exiling a Sneaky Snacker is very appealing in that matchup. Mostly this is just artifact hate that kills dual lands tho.
A 3rd Nihil Spellbomb is in the side for graveyard based matchups of all kinds.
3 Reckoner's Bargain are in the side for aggro matchups, such as mono-red of all kinds. In these matchups, you side out Fanatical Offering. While it doesn't leave behind a map, you can sacrifice a 5 or 7 drop and gain 5 or 7 life while drawing 2 cards. Ideally, you do this in response to removal, and get a nice lil 5 for 1 (6 life is worth 2 cards vs Red).
2 Thorn of the Black Rose is for grindy matchups, like controlly variants of Familiar, or just any midrangey deck running Kor Skyfisher with durdley artifacts. Side out Foundry Assembler for these.
4 Pyroblast is pyroblast. If you're in a blast matchup you probably have to have some of these to play the blast minigame. I may not like it, but this is what peak performance looks like.
Accursed Marauder is an edict to get around protection.
