Been using this one for over a decade. Works with Firefox’s bookmark keywords feature.

Make a new bookmark, set the link as follows:

https://lemmy.world/c/%s (or your own Lemmy instance)

And in the “Keyword” field, use “c” or “lemmy” or whatever.

Now, when you want to visit a specific Lemmy community on your home instance, you can simply type:

“c community_name” in the address bar, or “lemmy community_name” in Firefox and it will open the community.