fivewits wigs is an in US wig store and they do have character wigs. Cosplay fu is outside the US(I think) but I've heard good things! CosplayWigsUSA also is a wig company here in the US, and they have a good amount of character wigs.
That's about all I can think of!
Upcoming Conventions: Katsucon, Anime Detour, Wizard World Minneapolis, C2E2
Young Ana Amari- Overwatch
Miu Iruma- New Danganronpa Version 3
Sansa Stark- Game of Thrones (Season 7)