There are four big remaining proliferate cards to consider: the best is Yawgmoth, Thran Physician, which turns The Hollow into draw + removal and then you can spam proliferates for easy wins
2 The Witch's Vanity None of the chapters on The Witch's Vanity are game-breaking or mega-efficient, but getting three diverse, relevant effects on a cheap two-mana card is what turns The Witch's Vanity into a great draft card in black
Frankly, I've never ultimate-d him, because I'd always rather kill something or draw cards and drain life from various effects, but it's nice to know that you have a big effect that could win the game in one hit
Some of the items I'm most excited for are these two large folders, these are Portfolios for the game, meant to keep your cards safe
Only the first victory will earn you a reward
Flicker exiles a permanent and returns it immediately (same resolution)