I'll kick it off with my Top 10 Cards New To Modern:
- Assassin's Trophy: It's arguably not even close: this will become one of the premier removal spells of Modern. It hits close to anything at instant speed for cheap, and its drawback is mostly ignorable. It'll surge to a 4-of in maindecks and squeeze out other cards in sideboards. It might even warp other decks into its colours.
- Knight of Autumn: Another card for the obvious slam-dunk category, this is a GW Reclamation Sage that you want to board in against aggro. It's also quite maindeckable, as you can make it a 4/3 against control and combo.
- Discovery // Dispersal: This gives black something it's never had before: a decent filtering cantrip. It's great at filtering your draws in midrange and combo decks. Shame it doesn't play nice with Bob, though.
- Mausoleum Secrets: A powerful tutor if you can build around it, and Death's Shadow decks already build around it. They have the cheap cycler Street Wraith and the 1-cmc threat named Death's Shadow. Their removal is also cheap enough. Cycling- and self-mill-happy decks may also want this card, but it's a tougher call in those builds.
- Mission Briefing: I'm sure there are brewers out there who think 4 Snapcaster Mages aren't enough, or who want to recur spells and cheat their costs at the same time, or who need to fuel Pyromancer Ascension fast. This card is mainly for those brewers.
- Creeping Chill: It's good in only one deck: Dredge. But sweet sheesh is it good in Dredge! Free reach and life gain is nothing to scoff at there.
- Unmoored Ego: It does something no other Memoricide-like card does: it can boot lands. UBx decks tend to have some trouble against big mana decks like Gx Tron, so naming lands can cripple those predators for the rest of the game. And at least there's naming threats if you're too late to name lands.
- Experimental Frenzy: In the right decks, this can effectively draw upwards of 3 cards per turn, even though you can't play any more cards in hand until you blow this up. And since this card close to guarantees a land drop every turn, this has an incredible snowball effect the longer it stays on the battlefield. Shame it doesn't play nice with Bob or Ensnaring Bridge, but plenty of midrange and aggro decks play neither...
- Citywide Bust: This has a decent chance of being a one-sided enough board wipe for 3 mana (against Hollow One decks, Death's Shadow decks, Eldrazi, the Hardened Scales deck, Goyf, unlucky Humans board states...). This has a shot of seeing sideboard play.
- Vraska, Golgari Queen: She does a decent Nahiri, the Harbinger impression--worse card filtering, but significantly better spot removal. I suspect that'll be good enough for Modern.
There were plenty of honourable mentions this round, such as Ionize, Plaguecrafter, Legion Warboss, Kraul Harpooner, and Tajic, Legion's Edge. What are your Top 10 picks?