Wow great build man, its what I've been trying to do for a while on a grand scale, and it's cost friendly! Have you looked at Altar of Dementia? If it's on the field could be a response to someone unsumoning Dracoplasm, could potentially kill multiple opponents in the process.

Phyrexian Altar could be a good card.

Also Riku of Two Reflections might be another good option as a commander.

Hey just a quick note, you can't actually use Xenagos + Yasova to steal bigger creatures, since you have to choose a legal target when the ability is put onto the stack and yasova isn't buffed until after that.

If you don't mind me asking, what card is in the deck icon here?

Daedalus19876, it's just a basic Mountain from Dominaria.

If you don't mind me asking, why is Illusionist's Bracers in here? You don't have many activated abilities, but a lot of triggered abilities, so maybe Strionic Resonator would be a better fit.

Bear Umbra seems like it would work well here

Since you have at least 1 Gate in the deck, you should use Circuitous Route over Explosive Vegetation . Like the deck! =)

Hazoret's Favor doesn't work with Yasova, is there any other reason it is in the deck?