The icon component - available in both modes - will allow you to create icons from SAP UI5 font and also add custom fonts.
Example.
Here you can see the component. it is called "Icon" and has some general display properties. From the area "Standard Font" you can select some icons.
Or you can add custom font file and select on the second screen some content from the custom font:
Properties
The component is a simple one, so there is not much to introduce on it. You can change some properties for the selected icon.
Other relations
It relates to the SCN community component Fiori Button - SCN Design Studio Communitywhich has similar function set for the icon part.