Using Sketch, enter Edit mode on your text layer and ‘Select All’. Next, open the default macOS Fonts panel by going up ‘View > Show Fonts’. The toolbar within the Fonts panel contains a gear icon menu near the left, featuring a mysteriously named ‘Typography...’ option. That’s where the magic happens!

The Typography panel reveals which fancy font features are available for your selected text. For example, at the top you’ll often find a checkbox for ‘Rare Ligatures’ that enables more ornamental letter combinations.