Karmic Guide + Reveillark + sacrice outlet = infinite sacrifices, ETBs, and recursion of a creature with power 2 or less (Interesting ones listed here)
How it works:
- Sacrifice Karmic Guide
- Sacrifice Reveillark, targeting Karmic Guide and up to one other creature with power 2 or less in your graveyard with Reveillark's leaves the battlefield ability
- Resolve Reveillark's leaves the battlefield ability, target Reveillark with Karmic Guide's enters the battlefield ability
- Resolve Karmic Guide's enters the battlefield ability
- Repeat