There a number of posts out there that simply print the loaded fonts on iOS. This is a little bit more involved to sort and pretty print them to the console to easily determine what fonts have been loaded by visually scanning the list.

UIFont+PrettyPrint.swift

extension UIFont {
    public static func prettyPrintFontNames() {
        var fonts = [String:[String]]()
        
        for fontFamilyName in UIFont.familyNames {
            for fontName in UIFont.fontNames(forFamilyName: fontFamilyName) {
                var collection = fonts[fontFamilyName] ?? [String]()
                collection.append(fontName)
                
                fonts[fontFamilyName] = collection.sorted()
            }
        }
        
        for family in fonts.keys.sorted() {
            print(family)
            
            if let collection = fonts[family] {
                for font in collection {
                    print("\t\(font)")
                }
            }
        }
    }
}