If you have an app that relies on alternative frontends such as #Invidious, #Nitter and others, it's often hard to maintain a list of instances. I had that problem with #UntrackMe and #CastLab, so a CI job now runs every day to maintain a list of available instances.
I might add support for this to #Fedilab.
Source: https://git.holos.social/tom79/untrackme-rules/
Raw list of available frontends:
https://git.holos.social/tom79/untrackme-rules/raw/branch/main/payload.json