Not really a "project", but TypeScript's own type definitions for the DOM are a great example. Eg. document.createElement returns different subtypes of HTMLElement depending on the string argument (HTML tag name) it gets called with.
If you're a GraphQL developer, Pothos is the best example - all your user-defined types just fits in it like a glove 99% of the time. It definitely makes the most use of TS generics.