Gardevoir came to mind when I saw this thread but I realize the term fetish can be used in more social friendly ways. However this is the internet we're talking about so onto topic...
The idea of monotype teams be it of gym leaders or elite four members has always perked my interest and I've always tried to make one that works.
I'd love to fly on a glider or in a plane next to my staraptor =D
I'd like to cuddle something cute and small in my lap like a buizel, buneary, lillipup, torchic, mudkip, riolu, poochyena, zigzagoon, sewadle, vulpix, snivy or anything else I couldn't think of.
I'd always love to be in a gym (not pokemon gym) with some fighting types and train with them.
The idea of grass pokemonis truel amazing the way it's a complex living thing yet it gets its energy by photosynthisis.
If any of that fails then there's always gardevoir ;) No I'm serious I've got a level 75 gardevoir I'm raising named Garla with a level 68 gallade companion named galar so their names have the sam letters, just switched around. I love them in a double battle because they set up screens and cover their weaknesses. Gardevoir's thunderbolts keep the birds off of gallade with shadow ball to cover from ghost types while brick break and rock slide keeps the bugs and dark types off gardevoir. Psycho cut and psychic are their signature moves which they use in pefect syncronised harmony with eachother.