The Free Law Project is a non--profit organization that has assembled an archive of all of the free court orders and opinions available on PACER. The RECAP archive allows you to search by case names, docket numbers, and several other fields. See: https://www.courtlistener.com/recap/ .
The archive is updated on a daily basis.
One of the really neat things about the archive is that it allows you to run a full text search through all of the posted decisions. This is something that the to the best of my knowledge PACER doesn't allow you to do. You can search through the text of federal filings with Lexis Courtlink, but this requires a paid account.