MTG Salvation

The Initiative has proved to be such a strong keyword that I've added in both Seasoned Dungeoneer and Feywild Caretaker for extended testing... it's a really powerful mechanic.

Sky Maul for aggro, Halvar for midrange support.

Queen
Reconfiguration

This looks like a nice Figure variant to me, and I plan on giving it a spin in the cube.

Card can be very powerful, but we ran into consistency issues with it. There were times when it was a hard lock, but there were other times where the opponent was able to do just enough from underneath it to not make it worthwhile. It also limits your applications to mono-black, so it's a very narrow card. It can certainly be powerful, but we found that it was both just narrow and inconsistent enough that we removed it.

I prefer Finale.

I don't much care for counterspells with restricted target pools, but Force of Negation has been a good card for us. Much better than I expected.

I don't think any of them are particularly good cards if they're not crushing draw effects, so the one that has the biggest potential to change the outcome of a game when it matters is the one that has played the best for us. Flash is invaluable for having a meaningful impact, so 'Breacher/Thief have played better for us in that role than Narset/Leo.

Notion Theif is weaker than other cards with similar effects (hullbreacher, Narset, Leo).

I don't agree with this. I think the effect is significantly stronger than any of the other ones. It's likely worse than Hullbreacher (because it's only one color and 3 mana) ...but shutting off all extra draw and drawing the cards for yourself makes the effect far more busted than what any of the other effects have to offer. Narset and Leo are annoying when they interfere with your sorcery speed draw effects. Notion Thief is backbreaking when it has a meaningful resolution, and because it stops all instant-speed draw too, there's no workaround until it's removed. But giving all the stopped draw to you is just gross, and puts the power of the effect itself leagues ahead of the other hosers.

I've been super happy with it, and it's one of the dark horse cards that randomly steals games that people just never see coming.

Purse >> Pouch > Crawler

'Tusk > 'Chief

I love Seal, but it's definitely limited to decks with powerful proactive targets like combo decks and the like. It's bad for tutoring up generic goodstuff cards because it can't effectively be used to grab reactive spells (in most cases).

Embereth Shieldbreaker was the card I was waiting for when I was entertaining the idea of running Ingot Chewer.

If you can get the explore trigger on another attacking creature the turn this resolves, it's really powerful. Still good on its own, but it goes from good to great with if it generates full immediate value. I'll keep a close eye on this.