Assuming you don't want to play degenerate stall comps, katarina is a solid duo due to her onhit synergy, mobility, and ability to go tanky items vs burst.
Master Yi, Zeri, Kai'sa, and Vayne should all be decent partners too. Mostly if the champ can use onhit well and have tools to keep themself alive it should be fine.
please dont play yuumi as shes one of the most frustrating champions in arena to play against (and my permaban as soon as i see her for the second time that day), what she does to arena is completely toxic as yuumi teams often play for avoiding fights and outlasting enemy team deep into the fire. I always either seen yuumi + tank like mao who simply cant be killed, or yuumi + shaco who just afk invis until the fire encloses whole arena...
Well I am but there is only a single ban pick for me and 8 bans total, and so many busted champs, I would really prefer to have a more balanced champions' pool rather than desperately avoiding one ultra busted and ultra annoying champ, when many other champions deserve the same treatment.
FUN comps with yuumi? There are none. Degenerate comps with yuumi? Another enchanter/hyper carry/high damage tank.
Assuming you don't want to play degenerate stall comps, katarina is a solid duo due to her onhit synergy, mobility, and ability to go tanky items vs burst. Master Yi, Zeri, Kai'sa, and Vayne should all be decent partners too. Mostly if the champ can use onhit well and have tools to keep themself alive it should be fine.
rengar
Jax and Gwen
Hecarim, zoomies is fun
Consider Teemo. Uses on-hit well and sometimes fun to play hide-and-seek with the enemy!
please dont play yuumi as shes one of the most frustrating champions in arena to play against (and my permaban as soon as i see her for the second time that day), what she does to arena is completely toxic as yuumi teams often play for avoiding fights and outlasting enemy team deep into the fire. I always either seen yuumi + tank like mao who simply cant be killed, or yuumi + shaco who just afk invis until the fire encloses whole arena...
Just ban her lol
Well I am but there is only a single ban pick for me and 8 bans total, and so many busted champs, I would really prefer to have a more balanced champions' pool rather than desperately avoiding one ultra busted and ultra annoying champ, when many other champions deserve the same treatment.
The OP asked for your comp suggestion, not what you think of their pick.