(Another option that just occurred to me is to have Disciple of the Vault out, buried alive our loop + an artifact creature (preferably one that provides value), won't need the altars, so this costs 1-2 mana less, but requires more and doesn't give you the option of your library+infinite mana)
Fun fact: Damage marked on a creature disappears at the end of each turn, so your 1/1 chump can safely block a 5/5 if you give it indestructible first
I dont want to keep you waiting, so lets get right to the list
Every other creature comes with an EtB effect nowadays, so we would be giving too much value to our enemies
Phylath, World Sculptor, Obuun, Mul Daya Ancestor, Radha, Heart of Keld, Mina and Denn, Wildborn, and all the Omnath commanders are just some of the many lands matters commanders