Regenerator Blissey:
But on a serious note, Regenerator Blissey would be pretty annoying. Wish Passing would be ridiculous with this one, since you heal a teammate and Blissey at the same time, so this thing is sticking around for a LOOOOONG time. The extra bulk gained from Regenerator would easily rival the bulk Chansey gains from her Eviolite. Though that's not to say that Blissey herself would be a huge threat, since defensive Pokemon that can't hit back have a hard time standing out nowadays, and Blissey would be no exception. Would this be annoying as all hell? Yes, of course it would. Would this be a huge threat? Not that much more threatening then Chansey is.
Prankster Froslass: I think this is tied with Blissey as the most annoying Pokemon on this slate. With Prankster, Froslass has access to a whole arsenal of priority attacks, including Trick, Thunder Wave, Destiny Bond, Disable, Taunt, Spikes, Spite, and Pain Split. You can take down a sweeper not named Talonflame flawlessly with Destiny Bond, Guarantee at least 1 layer of Spikes, cripple sweepers and walls with Trick, and drain a Pokemon of its PP with Spite and make it easier for a Pokemon to revenge kill it. This is going to be very annoying, but at least Frosless won't last an eternity-and-a-half, unlike Satan. This gets my vote for sure.
Sticky Web Forretress: What make Sticky Web teams a shaky playstyle is the lack of a good Sticky Web user, with Shuckle being the best user, and even then, he's a little lacking. Sticky Web Forretress actually sounds like a decent idea, since he has Rapid Spin and Volt Switch for utility, as well as Explosion to safely bring in a teammate to sweep with and possibly weaken something enough for the switch-in to KO. He'd also be the only Pokemon in the game aside from Smeargle to have access to every field hazard move in the game, so he'd have some good versatility. There really isn't much to say here except that he'd be a pretty cool Theorymon.
Tinted Lens Flygon: This one... I'm not too sure about. On one hand, unresisted Outrages and Earthquakes are pretty sweet (Flying- and Fairy-types are still immune, mind you). On the other hand, I feel that he's still outclassed by Garchomp. Sure, unresisted STABs are nice to have and all, so Tinted Lens makes Choice Band sets harder to wall, but Flygon's stats vs. Garchomp's will always be steadfast in my mind. Is having STABs that can't be resisted really worth being an inferior Garchomp stat-wise? I'll leave that up to you all, but as for me, I'm not that impressed.