3 Combat Celebrant One For All, All 4/1 Combat Celebrant was deliberately designed not to produce infinite combat loops, but it turns out you can just make copies of Celebrant and exert those instead to set up as many combat steps as you need
Stonecloaker costs a little more for the same effect, but its also incidental graveyard hate, which is nice to have
The Collector Booster gives players immediate access to the coolest, most desirable cards from Ikoria: Lair of Behemoths
Auras, Equipment, and modified creatures you control gain hexproof until end of turn
Ramp For Counter-related stuff, there's Devoted Druid, Incubation Druid, Rishkar, Peeme Renegade, and a bunch of other stuff
I see this as a good value Elvish Spirit Guide however most people see it as an awful value Avenger of Zendikar or something