I hatched a Turtwig and Grimer with perfect IVs the other day. I also purified a Shadow Porygon and it ended up having perfect IVs as well. I'll keep it in the off chance that they'll have a Porygon Community Day at some point.
I purified a Shadow Vulpix and it turned out to have perfect IVs. I already evolved it into a Ninetales, although I probably should have saved it in case we got a Vulpix Community Day in the future. I'll just save one of my Elite TMs just in case that does happen.
Nope, never even truly tried because I have not played competitively once, I'm not interested in that (I would probably suck anyways, I'm just not a competitive guy, especially not in videogames). And to be honest I don't fully get the IV thing and I don't really care. Perhaps the closest was in the Let's Go games because of the judge feature. Heck, since I'm a lot more of a playthrough kinda guy and since the games have become way too easy since Gen 6, I actually try to catch Mons with not so good stats to try to increase the difficulty a bit.
Maybe, just maybe, in my most complete Home account I have a Mon that has close to, or just perfect IVs. Maybe I should look for it just out of curiosity.