There's also https://euroalternative.co in the same space
107 karma · joined September 27, 2016
Most of them can be self-hosted so you won't be locked in in case that happens again.
Enjoy!
The code for OpenAlternative is on GitHub if you want to use some or take inspiration.
As pre your comment about descriptions, I took them directly from the repositories where most of them brag about being "open source". That could be a good idea to modify that to me more informative.
I've tried to mostly curate the projects that are actively maintained, and have some sort of hosted, paid alternative. This gives you more confidence, that the app will be maintained as they're making money out of it.