Some of the bigger previous fan productions are:
Star Trek Continues:
https://www.youtube.com/user/StarTrekContinues
(A group of fans who have recreated The Original Series using all the big named characters to continue making episodes in that timeline)
Star Trek Renegades:
https://www.youtube.com/watch?v=eE2Wgop9VLM
(A fan film based upon the Star Trek franchise that features several characters from commercially produced Star Trek series, played by the same actors who realized them for film and TV. Directed by Tim Russ - Tuvoc from Voyager)
Star Trek Horizon:
https://www.youtube.com/watch?v=l94v4YOqxOc
(Another high end fan production that was released last week after a couple years in the making)