I started using notmuch[1] a couple of years ago and cannot imagine living without it. It can do free text search on almost a million emails (and probably much more) in a fraction of a second. I subscribe to a lot of mailing lists and add various tags on each making for some very powerful search queries.

E.g "from:torvalds and to:linux-ext4" to bring up all emails ever with those properties. Add some free text and/or "tag:foo" to narrow it down.

[1] https://notmuchmail.org