This is a rain team concept I had for ou. Pretty simple. Give feedback and suggestions where you see fit.
Evs 252 hp 156 def 100 sp def
A basic support set. Hp grass is there mainly for gastrodon and other bulky waters, who give tge team trouble. Toxic deals with walls (may replace with hypnosis) and encore is just to annoy. Ice beam can replace hp grass
Magnezone: choice scarf
Evs: 4 hp 252 sp atk 252 spd
Ability: magnet pull
Pretty simple: fast rain attacker and revenger. Gets rid of ferrothorn and other troublesome steels. Can provide switch ins for latias and vice versa, hp fighting is for primarily hitting ferrothorn while still being usable on other threats in rain.
Evs: 252 hp 4 sp atk 252 spd
The special sweeper, latias runs tge typical calm mind set, while functioning in and out of rain and covering the grass and electric weaknesses that threaten the team and taking the special hits. She also synergies with magnezone well and appreciates the steel removal he provides and is a good answer to sun teams. Life orb is also an item option
Evs: 252 hp 252 def 4 sp def
Physical wall and hazards. Also spins for gyarados. She'd shell is also an option of course
Gyarados life orb
Evs: 4hp 252 atk 252 spd
Physical sweeper who loves the rain and brings tge pain. DD boosts, waterfalls stab, earthquakes for electrics and ice fang for grasses and dragons. Breloom and him have decent synergy as well, as do him and Magnezone.
Breloom: choice band
Evs: 252 atk 252 hp 4 sp def
Priority. Plain and simple. Also kills water/grounds like gastrodon who are a nuisance and other annoying threats like magnezone and rotom w
Well that's it. All suggestions welcome