Bug/Steels are rarer in OU, there's only Scizor.Don't forget this is UU, Bug/Steels aren't very common in this tier.
For that Sealeo, you definitely need Toxic Spikes support. And a spinblocker. However, Venomoth can just come in, suck up the spikes, and start Quiver Dance spamming. Sealeo's 45 speed doesn't help either.