Yeah, wallbreaking Clefable is annoying to beat. iirc, I used Support Mismagius before and that worked fairly well. Immunity to Double Edge, and low weight basically forces Clefable to use Fire Blast, which doesn't 2HKO and can be PP stalled eventually. It can also Taunt Calm Mind sets so they can be worn down more easily by the rest of your team, and if you run a bulkier spread, it won't be 2HKOed by a +1 Thunderbolt or Ice Beam. Out of the three sets, it only really fears being Tricked Toxic Orb, and that can be played around (or Taunted if it doesn't Trick on the switch). It's not really ludicrous to run support Missy on a stall team either since it's a decent spinblocker, and it deals with opposing stall really well.
I think there's a few other things too though. RestTalk Uxie, Specially Defensive Arcanine, and Dusclops are pretty reasonable other options, and then there's a bunch of NU stuff that does well too (Shuckle, Torkoal, Probopass, Magcargo...). As far as Trick + Toxic Orb goes, you don't really have anything that's completely safe against it, but keep in mind that it can only use it once, unless it gets the Toxic Orb back. Also, Trick + Toxic Orb isn't really that deadly imo, since you can generally force Clefable to Trick a Pokemon with reliable recovery, and from there, you can just switch around a bunch to mitigate the effect, and keep the Pokemon's HP up with their recovery move. Calm Mind is different to beat, but Haze Milotic is a good answer to remove CM boosts and PP stall (though it dies to crits and parahax), and Perish Song and Trick to beat it if it's the last Pokemon.