Fanart is probably the second thing people think of when they think of fandom.
As is probably obvious, fanart is when people take (usually) characters from stories, games, movies, etc. and create art around them. Drawings are probably the most common, but there’s also jewelry, textile art like knitting or cross-stitching, stuffed toy versions, etc.
I personally rather like fanart. There’s a lot of really talented people out there and I like to see what they come up with.
If you’d like to peruse some fanart as well, I recommend DeviantArt. Their search function is excellent and there’s a lot of excellent artwork up on there.
In general, fanart is less controversial than fanfiction, probably because people feel like it messes less with the core of the characters, excepting NSFW fanart which you know exists because this is the Internet. And while I am not an artist, it seems to me like fanart creators are less looked down upon by “real” art creators than fanfiction writers tend to be by “real” writers. (I may be completely off-base there. Let me know if I am.)
Are you a fan of fanart? (Har har.) Have a favorite piece or artist you’d like to pimp? (Please make sure you credit the original artist if at all possible. Poor people have enough Internet piracy on their hands.)