What does TR Magearna run? Any good replays and teammate suggestions? TR is only an "other option" on its analysis. I see TR Magearna picking up traction.
Finch got the set, but I'll add I think focus blast is massively superior to ice beam, as just about anything ice hits fleur or tbolt will handle. Team mates for TR mage depend on whether it's run on full TR, semi-TR or as a one-off sweeper. Full TR usually involves some combination of: Mage, Cress, Crawdaunt, Alola-wak, Stakataka, a slow powerful mega (maw and cross most common) and a suicide TR lead like Uxie. The idea of this team is to basically always have TR up and Mage can be setter, sweeper or both. To be honest I find full TR pretty lacking as a playstyle although it does mess up a lot of other playstyles.
Semi-TR can come in a couple variants. Mage plus additional TR setter-sweepers or Mage plus a TR abuser or two (crawdaunt is most common). These teams are less about having trick room up all the time and more using trick room strategically to blow open a game or finish an opponent off. My sig has an RMT with semi-TR and you can find lots of replays just by searching me. Also Aim used it in his road to #1 session 15 as his featured team so you could just watch that.
One off Trick room is a shift gear mage that trades unlimited turns of being faster for better bulk and slightly better power. It has the same kind of team mates as shift gear. The extra bulk wins some matchups, but because TR is really short it can't do things like double dance that shift gear can.