Looking through TS definition here I still can't seem to find all the possible types of fabric objects, I can't find a list of types on fabricJS documentation page either: https://github.com/DefinitelyTyped/DefinitelyTyped/blob/06aceea74ca33b2217dcd9f5c53fd9cb1148ff62/types/fabric/fabric-impl.d.ts
The list below is taken from http://fabricjs.com/docs/, although it appears that the official list is out of date so I've added the Textbox class.