Someone made a multi-instamce search that is pretty great imho. its at https://fedi-search.com . You can choose which search engine you like even. I just added the favicon to my bookmark bar and use that when I specifically want Lemmy results.
The wildcard works too, so site:lemmy.* will show you results from more instances than site:lemmy.world but will still omit stuff from instances like beehaw.org for example.
I suspect that there's going to be a more elegant solution to this problem in the coming months.
Wish there were a way to search across all Lemmy instances, even ones without the word Lemmy in their name. Maybe that’s something Google themselves will implement eventually?
I have submitted "!lemmy" to DDG as one of their Bang indicators. See if it gets approved. Saw this topic over on Lemmy.world where someone mentioned this, but it seems like i cant login into lemmy.world or crosspost, or even see all teh comments on this page. Still learning!
They said you can put quotes to it like
Pear “Join Lemmy” OR “Powered by kbin”
The “Join Lemmy” the commenter said, is on every lemmy server’s page, so it can help capture results from servers not following lemmy.*
Pear site:lemmy.* OR site:kbin.*
would miss things from many servers not following this naming convention
I think as the top comment here said, there are tools people make to help search the fediverse. There will be a good way to search it if it did become very popular