The first non-Pokemon avatar/sig theme I used was Zero Kiryuu from the anime/manga series Vampire Knight, which was one of the few non-Pokemon anime I ever watched and I grew a fond liking towards him (must be the White-Haired Pretty Boy effect).
If one looks at most of the new ones I brought out in 2012 and 2013, most of them had male-looking appearances or featured male characters. I still use female-looking themes, but oh god that genderbending phase I underwent in 2012 defined my usual choices for themes these days.
The diversity of my themes expanded even more after becoming Supporter, I showcased some Black 2/White 2 characters for a while, such as Elesa, Colress, Marlon, Roxie, Iris, Cilan, Cheren and Bianca (the avatar I used for the Bianca theme had blinking eyes too). Then I eventually returned to my usual "odd but unique" themes (like the one I have now) while also mixing a few anime-based ones in after getting inspired by members on both PC and Ever Grande City.
The gif in my current sig originated from a random browse through Tumblr and I thought it'd make a great signature. I did a test run with it and I was surprised at the reception it got, someone even said that if I only introduced this one before MOTY 2012, it would have given me a first. Don't be surprised if this sig alone steals all the Best Signature votes in MOTY 2013, due to its randomness.
However, despite everyone loving this sig, one member who regularly browses the TCG and New Users/Welcome forums apparently thought it was "creepy". To be honest, I don't get why someone would find a gif of someone pulling out a Connect Four "creepy", but I guess it must have been the facial expression he found creepy hahahaha. He even kept telling me to take this sig down but being Hikari10, I always like to keep sigs I find hilarious with both me and other members.
No wonder I reuse this one a lot, cos of how very "Hikari-ish" it became.