Not only is the proliferate keyword tied intrinsically to the Phyrexians, first appearing in Scars of Mirridon, there were counters all over the shop in Standard at the time, from sagas, to brand new counter types like stun and shield
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
The Collector Booster gives players immediate access to the coolest, most desirable cards from Ikoria: Lair of Behemoths
Forced Transformation: The Oracle spell Foxfire and Beowulf's sword skill "Chicken" can cause enemies to turn into Chickens if their Brave drops low enough
With that in mind, heres a look at the rarest and most expensive Magic: The Gathering cards, why collectors covet them and how much theyre selling for
I see this as a good value Elvish Spirit Guide however most people see it as an awful value Avenger of Zendikar or something