For a deck that can basically split one enters effect into two with offspring, that scales into four enters effects with Panharmonicon
For example, a 3/3 creature with trample blocked by a 2/2 creature can have 2 damage assigned to the blocking creature and 1 damage assigned to the defending player
Mangara, the Diplomat Mangara, the Diplomat is a great blocker as a 2/4 lifelinker that gives you a card whenever an opponent casts a second spell or uses two or more creatures to attack you or a planeswalker you control
This singular card is the one that made me question the FlickerFlicker synergy criteria, because it doesn't have anything to do with that strategy, and yet it's an absurdly powerful card
But its pretty much a color-shifted Melira, Sylvok Outcast for decks that might not want to deal with the legendary creature clause
Coming down untapped and immediately giving you two mana, Ancient TombAncient Tomb is some of the best fast mana that money can buy, getting you a full turn ahead by just playing a land