Combos:
NECROSYNTHESIS +SCURRY OAK + ALTAR OF DEMENTIA
Activate Altar of Dementia by sacrificing a creature, milling player equal to its power
Necrosynthesis (on the oak) triggers, putting a +1/+1 counter on Scurry Oak
Scurry Oak triggers, creating a 1/1 Squirrel creature token
Activate Altar of Dementia by sacrificing the Squirrel token, milling target player four
Repeat from step 2.
Infinite mill, infinite squirrels, infinite colorless mana

SCURRY OAK + IVY LANE DENIZEN
Reqs: denizen on field. Cast the scurry oak. Denizen trigger, put counter on oak. Repeat.
Results: infinte etb, infinitely large oak, infinite squirrels.

CHAIN OF SMOG + WITHERBLOOM APPRENTICE
Reqs: Witherbloom Apprentice on the battlefield (or enough mana to cast both)
Cast Chain of Smog targeting me
Witherbloom Apprentice triggers, causing each opponent to lose one life and I gain one
Resolve Chain of Smog, discarding two cards and choosing to copy it, targeting me w/ the copy
Repeat from step 2
Results: infinite gain/drain, win