Might be interesting for you as Quick Win within the Debugger:
(lldb) po [UIFont fontNamesForFamilyName:@"Helvetica Neue"]
(id) $1 = 0x079d8670 <__NSCFArray 0x79d8670>(
HelveticaNeue-Bold,
HelveticaNeue-CondensedBlack,
HelveticaNeue-Medium,
HelveticaNeue,
HelveticaNeue-Light,
HelveticaNeue-CondensedBold,
HelveticaNeue-LightItalic,
HelveticaNeue-UltraLightItalic,
HelveticaNeue-UltraLight,
HelveticaNeue-BoldItalic,
HelveticaNeue-Italic
)
November 2018 - Update
A new swift-y reference for "Custom Fonts with Xcode" - by Chris Ching. I had to update, as this is a great value posting for the new way combined with all missing parts to use custom fonts in a project.