Recently we updated the pyxform repository readme with a big list of XLSForm related projects, which the community here may find useful.
The main criteria were that the project seemed to be in a functional state (i.e. not an abandoned WIP), and updated within the last few years. Projects weren't thoroughly reviewed or validated, so be sure to do that before using one.
If you have any projects that you want to call out - projects to add or remove, or kudos to / endorsements of projects on the list - please comment below.
Thanks!
PS. There are quite a few projects built around ODK Central as well, so something like this could be added to the pyodk repository in future.