Not starting guides, like jlai.lu it's there but some links deep hidden. This is such an obvious user experience problem that this - in my opinion - needs to be featured prominently in the main sidebar. Almost everywhere you have to dig deep to even understand that you cannot find all the communities hosted on other instances, unless you use these tools, or have a huge instance like world so basically everything is subscribed to by somebody.

That's why mander.xyz, lemmy.ca and aussie.zone get my gold award :)