Let's see, let's see...
Lucario (Nora) was used in Cool Contests (I know, overused. Frankly, it's not like I know what pokémon's used in what Contest type, of all things)
Ninetales (Foxy Loxy) was used in Beauty Contests (Somewhere... I can hear someone sayin' I mimicked that one kid in that one Pokémon ep when Brock gave away Vulpix.)
Dragonite (Rydia) was used in Cute Contests (... I think it's cute tbh. Shaddup.)
Starmie (Starfy) was used in Smart Contests (Actually, how DO you judge Smartness? Heck, how many nerdy pokémon even exist?)
And finally, I used my Rhyperior (Taizo Hori) in Tough Contests.
And yes, I do suck a LOT when it comes to nicknames. Frankly, I'm no good at originality, but from what I've saw in R/S, nicknamed pokémon appeared to do better than non-nicknamed ones. That, or my Ruby game is wonky as eff. *shrugs*