Cao Cao, Lord of Wei

T: Search your library for a legendary card, reveal that card, put it into your hand, then shuffle.

Each creature assigns combat damage equal to its toughness rather than its power.

Haste T: Create a token that's a copy of target nonlegendary creature you control, except it has haste. Sacrifice it at the beginning of the next end step.

Whenever another creature dies, you may put X +1/+1 counters on Kresh, where X is that creature's power.

Mikaeus enters with X +1/+1 counters on it. T: Put a +1/+1 counter on Mikaeus. T, Remove a +1/+1 counter from Mikaeus: Put a +1/+1 counter on each other creature you control.

You don't lose unspent green mana as steps and phases end. Omnath gets +1/+1 for each unspent green mana you have.

Flying XU/B: Choose a color. Target opponent exiles the top X cards of their library. For each card of the chosen color exiled this way, create a 1/1 blue and black Faerie Rogue creature token with flying.

Protection from everything If Progenitus would be put into a graveyard from anywhere, reveal Progenitus and shuffle it into its owner's library instead.