Ragamuffin's Hat 39% of decksPercentage of decks that could play both Chorus of the Amphitheater (Blue) and Ragamuffin's Hat that play both
In terms of synergy, consider: Titania, Protector of Argoth, to profit off sacrificed lands Crucible of Worlds or Ramunap Excavator to keep the land train going Scapeshift or Crop Rotation for explosive plays Greater Good to bin huge creatures, then cast them again from the graveyard for a single land This card wants to be in any deck that flirts with graveyard recursion or land sacrifice
Jackal, Genius Geneticist Jackal, Genius Geneticist might be the weirdest +1/+1 counter commander
There are probably a couple of other quirky things you can do with the tribe too
In general, you can look at what makes Uril, the Miststalker decks tick and copy some of those tricks
Zimone and Dina Zimone and Dinas ability to essentially cast a Growth Spiral once or twice a turn makes this card a very useful commander for ramping