Alazir

It's a very unique field that complements Serra really well and manages to add flavor and new strats with Ice type mons. It honestly deserves more love.

I never really got the complaints about the RNG-ness of it. Like I've never had a problem mitigating those things. Synthetic Seed, Lax Incense, and there are several "beam" moves available to you that can burn right through her team. Nature Power gives you Mirror Shot, which is boosted and counts as a beam, and Flamethrower also counts as one. Idk, it was always a respectable and fun field to play in for me.

Honestly, I've never had any problem with it. Just using Special moves substantially reduces the RNG-ness of it, and it's not like it's particularly difficult to take advantage of that aspect yourself you you were so inclined. I've never personally lost to Serra's Gym Battle myself, so I haven't had the same frustration that seems to plague most of the community.