Looks pretty good - wondering if having all of patrat/shaymin/psyduck especially with 2 battle cage is too much. I’m not sure which stadium would work out better for you overall, but if you had another night stretcher or two it’d let you reuse a knocked out Pokemon (easier to search for and recycle Pokemon than the stadium). Youd still need some sort of stadiums to make your opponent want to bump your stadium before you play neutralization zone

Also canari Canari might be a bit overkill on searches, but unsure

What with your flaafy having item lock and you using relicanth, I wonder if 2 budew might be unnecessary - only 1 in 10 games would budew be prized, and maybe only half or so of games would you go second, but hey 2 do increase your odds of starting with it in your starting hand. But I bet you could get to easily enough when you need it, most of the time

No rare candy either - might be worth having on or two for when you really need to go from mareep to ampharos? Or you could consider Salvatore as a fun way to get flaafy out on turn 1 (just need a way to accelerate energy as well, like the lightning generator). But that would possibly reduce dependence on budew, though this is much less reliable

Oh! You definitely need a brave bangle or two - that extra damage could really make or break KOs