AlternativeTo lets you find apps and software for Windows, Mac, Linux, iPhone, iPad, Android, Android Tablets, Web Apps, Online, Windows Tablets and more by recommending alternatives to apps you already know.
It’s a great place to find alternatives (including opensource alternatives) to services and software.
In Eternity (the app I use to browse Lemmy), the sidebar is equivalent to the “About” tab of a community.
I’m on Eternity too… Is the sidebar the swipe-able tab in a community?