PS4 has earned great support from a wide variety of game publishers, including many indie developers. Since February 2013, the number of developers joining has increased from 126 to 505.
With a few hours of research I added to the list released by Sony itself in February the studios that announced games in development for the PS4 since then. This allowed me to identify 158 studios. You can see them in the table at the bottom of this post (feel free to add your own discoveries in the comments if I missed any). I also included the titles of the games that have already been announced (or that are rumored with any semi-solid backing) and color coded them to identify the games that have already been confirmed as exclusive or multiplatform for reference.