The most up-to-date source is the CLAP Audio Software Database:
This project is run by Martin Diers (a.k.a. teilo) who set up a database of all available CLAP plug-ins and hosts. Submissions are made on the page through the feedback form, or by posting on a forum thread at KVR:
https://www.kvraudio.com/forum/viewtopic.php?t=583501
Developers can also request an account there and maintain their own titles.
This list is not necessarily complete and will be expanded in future updates
This list is not necessarily complete and will be expanded in future updates