Basri's Lieutenant + Cathars' Crusade + Altar of Dementia
Basri's Lieutenant
Cathars' Crusade
Altar of Dementia
Infinite death triggersInfinite creature ETBInfinite creature LTBInfinite millInfinite creature sacrifice triggersInfinite +1/+1 counters on creatures you control
How it works
Activate Altar of Dementia by sacrificing a creature with at least one +1/+1 counter.
Basri's Lieutenant trigger, creating a 2/2 Knight token.
When Knight token enters the battlefield, Cathars' Crusade triggers, putting a +1/+1 counter on each creature you control.
Resolve the Altar of Dementia ability, causing target player to mill cards equal to the sacrificed creature's power.