As of 2020-12-23, I'd recommend the following clients:
Lagrange (prebuilt Windows & MacOS binaries)
Deedum (available from Google Play)
Elpher (available within Emacs MELPA)
The first two are standard-ish GUI programs for mainstream platforms. The
last, "elpher", is a text-mode system which may be run inside Emacs, and
which imports all the affordances of that editor, such as they are.