Sun Titan + Fiend Hunter + sacrifice outlet = infinite sacrifices and ETBs
How it works:
- Have Sun Titan and a sacrifice outlet on the batllefield
- Cast Fiend Hunter, exiling Sun Titan with Fiend Hunter's ETB ability
- Sacrifice Fiend Hunter, returning Sun Titan to the battlefield
- Return Fiend Hunter to the battlefield using Sun Titan's ETB trigger
- Repeat