There’s also Lemmy Instance Assistant. It has multiple features but my most used is that if you end up on another instance it adds a link to take you to that same post/community on your home instance.

It hasn’t been updated in quite some time but the dev was active on Lemmy not too long ago and it continues to work fine for me.

There’s a community here, links in the side bar: lemmy.ca/c/instance_assistant