There's no actual limit to the number of catalogs you can add to the Courses Catalog Management list or to the Custom Page widget. The only limit is the following one:

Please Note: the page widget can only display up to 24 cards per catalog.

Hello! We have 455 catalogs and find it very difficult navigating through the course catalog screen in the Admin menu to find a catalog to make edits to the settings.  Are there plans to add a search feature?  Thank you!