Ulamog, the Infinite Gyre

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.

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.

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.

Flying When Sharuum enters, you may return target artifact card from your graveyard to the battlefield.

Flying T: Destroy target creature. It can't be regenerated.

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

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