GoToSocial frontends
Here are some of your frontend options for using a GoToSocial node. This isn't an exhaustive list- many Mastodon clients are also compatible with GoToSocial.
Phanpy
A frontend with a large number of features. See Phanpy's readme for an introduction.
EnaphoreEnafore / Semaphore
https://enaphore.socialenafore.social/ and https://semaphore.social/ are lightweight clients based on the Pinafore project which was retired in 2023.
Others
List of Mastodon clients, many of which are compatible with GoToSocial.