I think it depends on what gear you're planning to equip, if your equip costs are generally insignificant then you can just pay them and save the card slots, but if you run stuff that's more than 2 mana to equip (or has a more exotic equip cost) you might enjoy stuff like Ardenn. I think my deck has 10 equipment and 3 free equip sources, though each of those equipment synergy cards does other useful stuff. I think if you ignore the big hammer my deck has 9 equipment averaging to 2 mana to equip. As for how useful they prove, I have found that free equip costs can be incredibly swingy, letting you do stuff a turn or more early can be huge. If you draw multiples of the effect and have no equipment it can suck, so I'm sure with 3 synergy pieces I could benefit from more than 10 equipment.

It's about as fun as having a 'kick each other in the nuts' competition for game night, but I feel like this Commander would benefit from some stuff like Merciless Executioner, Plaguecrafter, and Accursed Marauder. The idea is you just play one of the many variants on the theme (there are many more), sacrificing itself each time, and then get it back to play again next turn. I had to limit myself in my Meren list to only 3 of them (and no Grave Pact enchantments), but depending on your play group it could be a significant inclusion.

Cool card! I agree it's probably not as good in most decks as Brawler, but that doesn't mean it's not a fine card in it's own right, costing only 3 is a real upside! I have multiple decks that might like it!

The drop rate of new cards has become unhelpful, even someone with a fair bit of time to invest in a hobby (me for example) can't really see everything new, so thanks for pointing Revenant out!

I'm not sure if I mentioned it, but Brash Taunter is bloody hilarious with Scavenged Brawler or Qarsi Revenant, Brawler gives you a beefy aggro blocker that can beat stuff to death, Revenant lets you ping anything to death, and both give the Taunter the key lifelink ability, very useful when he fights the biggest things on the board. The funniest part about using this is that the base creature is indestructible, and you're not equipping/aura-ing him, so some colours have almost no way to answer Taunter once it's resolved.

I'm a fan of Diabolic Revelation, obviously a bit of a build around. I think most tutors suffer from people wanting them to be almost as good as Demnonic/Vampiric Tutor, and those are badly designed/broken cards that ate bans, yet because they exist they normalize something that hurts the game. Diabolic Tutor sees a surprising amount of casual play, and I think that's a reasonable card.

I also enjoyed Transmute, but I will forever be doing penance for having actually cast Brainspoil, is that actually the worst removal spell ever printed? I think it's worse than the Portal stuff, 5 mana for sorcery speed conditional removal with an upside that almost never mattered from the day it was first used? I know they didn't want it to be a good spell, but even Murder was only 3 mana, and this is MUCH WORSE than Murder. I still wonder if they'll do something like Transmute for Boros, only it's restricted to finding Artifacts/Enchantments to keep it from being too useful. I just hope they don't nerf the spells THAT hard.

Just getting back to you about Omen of Fire, I've tried to slip it into a few decks, and the biggest complaint I had was that the decks I wanted to use it in were low enough in power level that people would sometimes balk if they were hit too hard by the land hate aspect. I think if you're allowed to use Game Changers (Bracket 3) you shouldn't get too much negative attention for Omen (expect some though). It's also a meta call, if nobody uses White or Islands then the card can do absolutely nothing. The Instant speed nature of it can matter in some lists, if you play it on a Blue player's end step then they can't replay any of the Islands that turn (and might have to discard a bunch), whereas a White player might have to choose between losing their blockers for the turn or sacrificing their aggro creatures, especially if they don't have a lot of Plains. FWIW a LOT of 'go wide' type token decks use White tokens, this will wipe out those tokens.

Omen plays well with cards that help your interaction get through, like Vexing Shusher for example, because you might find that the decks you most want to hit with it are best suited to just counter the spell.

Omen gets a lot worse if you're playing against people who use untyped duals, but I will note that more and more people like using things like the Surveil lands and Triomes, meaning even if people aren't on OG Dual Lands they can still have access to plenty of playable typed duals, and FWIW Omen is MUCH better vs ETB tapped Islands. If you find people react to you running Omen by running more of these untyped duals you can start using Primal Order that punish people for using non-Basics (I feel like you could probably get away with running a lot of Basic lands in a Gruul list, ymmv), so people are hurt either way.

Hopefully that can help give you insight into running Omen in a deck of your own!

I'm not sure if it's really an issue in your metas, but I found that when I built infinite combos it was often a big asset if I had some different types of payoff; this could help me get around protection effects in some cases. Anyways, Altar of the Brood allows infinite creature ETBs to mill out each opponent, all without targeting, and they die when they draw their next card. If nobody ever has Protection or some from of damage immunity then this isn't relevant and sorry for wasting your time!

I have a fancy Inkmoth Nexus that does essentially nothing ATM, but your idea of using it with Kessig Wolf Run seems reasonable, I think I might add it to my own Gruul list, it even wants some Colourless lands. Thanks!