Anyone know of pack strap fasteners you can buy?

I would shorten them. If you don’t want to do that, you can roll up the excess and fasten with a piece of velcro or rubber band.

Seek Outside packs come with little Velcro strips that attach to the end of the strap so you can roll it up and fasten it. You might reach out to them or maybe they’re sold somewhere else.

What you want is normally called a “strap keeper”. The lightest option is shock cord or an elastic band. Tom Bihn and assorted tactical companies make more robust ones. If your straps can be detached at one end, a loop of elastic webbing will also work.

Thanks guys! I didn’t know what they were called.

Velcro One Wrap

O-Rings.

https://www.homedepot.com/b/Plumbing-Plumbing-Parts-Faucet-Parts-O-Rings/N-5yc1vZckgy