>>34285381Literally just Skarmory. Lando has no hard counters, at least one of its sets can deal with every Pokemon in OU. This is why it has hegemonic-level usage, there's zero reason not to have it on your team. The only thing that can attempt to deal with it is Skarmory and that's only because it can wall and phaze Lando. It can't even OHKO. That's as much of a "counter" as you'll get.
That being said, there are tons of things that can easily revenge kill it, and it also has a bit of 4MSS thanks to the diversity of its sets. This is what prevents it from being outright banned. But when the only bad things you can come up with about a Pokemon are "its movepool is too wide" and "it's theoretically possible to KO it", well...