Simic's Amalgaming

(You may cast a legendary sorcery only if you control
a legendary creature or planeswalker.)
Choose 3 creature types. For the rest of the game, creatures you control and creatures you own that
aren't on the battlefield are those 3 creature types
in addition to their other types. Then, creatures
you control gain +1/+1 until end of turn for each
of their creature types.
Pefection at any cost.