Anime and gaming console inspired costumes were predominant, but there were a number of original designs.
I was lazy this time around and only had a couple of costumes, which mostly loosely based on H. P. Lovecraft’s Cthulhu Mythos. I had purchased some Mythos patches from Propnomicon a few years back and they have come in handy. One of the other Propnomicon patches was from the Miskatonic University, which I attached to a blue blazer and worked well with a nice 60s Stetson fedora, a pair 30s glasses with my prescription inserted, which completed the costume for a Miskatonic U. “Professor”. I also added the Miskatonic U lapel pen, but it's hard to see in the photo. The other gentleman in the photo, Capt Gordon I believe, is from the Arkham Asylum, which although HPL inspired, is of the Batman/Joker timeline. It worked well together for the photo nonetheless.
Here are twenty two additional photos by another MobiCon attendee, Mike Kittrell: http://photos.al.com/4558/gallery/mobicon_xviii_may_23_2015/index.html#/0
MobiCon attendee Eris Walsh of the site She Geeks has a great, in-depth post: http://she-geeks.blogspot.ca/2015/05/mobicon-happened-and-i-was-there.html
As more attendees post their galleries (and I find them), I'll put the links here.