The Tableau REST API does not offer a method for retrieving a user’s Favorites.
However, I learned from Tableau Support that the Tableau internal Postgres database contains this information in the asset_list_items table. Note that Favorites aren’t mentioned anywhere in the documentation.
Here’s a query for my Favorites for a particular site. Join the results to the “workbooks” and “views” tables to get more information on the results.
select * from asset_list_items ali join asset_lists al on ali.asset_list_id = al.id join _users u on al.owner_id = u.id join sites s on al.site_id = s.id where s.name = 'Default' and u.name = 'eva'