Xcode custom fonts not showing up in Storyboard
I know this is a pretty old question, but I ran into the same issue. And the above tips didn't work for me. Apart from the standard checks (present in bundle, restarting XCode, the thing that fixed my issue was that my label text type was marked as "Plain" and hence some fonts were not showing in the dropdown in the Storyboard. As soon as I changed the text type to "Attributed", all the fonts appeared in the dropdown.
Hope this'll help someone stuck with the same issue.
Had the same problem but this SO answer by user Saranjith solved it while the other solutions in this thread didn't: Xcode 8 custom font doesn't show up in interface builder
Basically in Font Book select "Computer Fonts" and then hit the + button and re add the Fonts.
This is happened to me after moving to Xcode 11 in Catalina from Xcode 10 in Mojave.