I nickname virtually every single Pokemon I find, the exceptions being Pokemon I don't care for at all (like Audino, at least for now). I usually put a lot of thought into the nicknames and try to come up with something cool. They range from real human names, to words that I feel fit, to references to characters or objects from fiction and mythology. I sometimes put way too much thought into it.
My most creative I'd say are...
Ouroboros (Snivy) - Picked this because the
titular symbol represents nature and also depicts a snake. Thought it fit the Snivy line great.
Vanguard (Watchog) - Didn't nickname my Patrat, but when I saw Watchog's bad*** glare and pose, I had to call him Vanguard because he looked so brutal and powerful. It turned out to fit amazingly as he started learning brutal damaging and incapacitating moves.
BrightEyes (Blitzle) - Had a female Blitzle and decided to name her (and all future horse Pokemon I get) after My Little Pony characters, so I went to a list of all characters (including the new series and the old toy line) and chose Bright Eyes.
Valentino (Woobat) - Wanted something intimidating to fit the bat thing, but also something that fit "lol hearts", so I chose this Italian name because it makes me think of mafia.
Atropine (Venipede) - Named my Venipede after a poison, and spent a few minutes looking up different kinds, ultimately settling on this one because I thought it sounded really good for Venipede's appearance.
Kremlin (Sandile) - Sandile just screams "Kremling" from the Donkey Kong Country series, but I wanted to call him "Kremlin" (lacking the G) because it sounded cooler, so I guess technically he's named after the building. :bleh:
Viktor (Magnemite) - Got Magnemite from the Dream World and knew I had to give him a really good nickname because I like him so much. Chose "Viktor" out of two spellings for the same name (the other is "Victor"; the one I chose is the Russian version). I chose this name because of an abstract mental association I had, which went something like: Magnemite -> Electricity & Machinery -> Victor Frankenstein's iconic metal laboratory -> lightning to animate the monster -> Victor.
Gregori (Arceus) - Wanted something epic to fit the "Jesus Pokemon" as I call him, lol. I picked Gregori, after
the Watchers, a group of angels also called by that name... except I just found out I misspelled it. Better go to the Name Rater, lol. Should be "Grigori".