I have used Wait Times for Disneyland. On my last visit a few years ago found the times to be pretty accurate. The app allows others users to input their wait times, so it is constantly being updated.
I used to use Mousewaits and DL Wait Times, but since Disneyland released their own official app, that's pretty much the only one I use. It has the current wait times (fairly consistent with what you'll find on the times boards in the parks and at the ride entrance, but there is about a 5 minute lag between when times are updated on the boards and when it shows up on the app) and current FP return times (that seems to lag about 10 minutes in this case).
My go to is the official app. Seems mostly accurate for wait times. I also use it to view menus and have even made a 9:30 a.m. reservation at 9:00 a.m. to Ariels Grotto walking into the park for breakfast.