For me, it really depends. I don't go out of my way to use my favorites in every team that I make because naturally every pokemon doesn't fit well into every type of team. However, whenever I do use my favorites, I use them in OU regardless the tier. As for what these pokemon are, I'd say a decent list is... Breloom, Ampharos, Froslass, Piloswine, Gastrodon, and some others as well. Some of those pokemon are OU anyways, so when they go on an OU team it's not really any different, but with like Amphy and Froslass, they usually catch people off guard since they're like... NU and UU. With Piloswine I gave in and just use Mamoswine on my teams (I think it looks kinda weird, but wev) HOWEVER when I use a swinub in the games I just don't evolve it past Piloswine xD
But yeah, I dunno. Ampharos is pretty versatile. The only sucky part is that Raikou has his exact stats but a little better. HOWEVER I still use Amphy anyways. He can fill all sorts of roles. In the past I've used him as a bulky revenge killer of sorts (Either Leftovers or air balloon, lots of def evs, Thunderbolt, T Wave, HP Ice (those dragons never suspect it), and volt switch. Also, his agility set with more offensive EVs and Nature is good too (I use pretty much the same set). And most recently, I've used him as a Dual Screener for an HO Team xD I'm pretty sure Raikout can't do that ;P
As for Froslass, I only use one set for her. Spikes, Taunt, Ice Beam, and Destiny Bond. That one's really fun to use That way you can either use her as a lead or a back up lead, lay out some hazards (Or decimate a grass or dragon type), disrupt set up pokes, and then try and take someone with you on the way out. it's good fun.