https://www.openwall.com/passwdqc/

passwdqc is a useful toolset for password/passphrase strength checking and policy enforcement and includes an optional pam module.

My use case is that I'm trying to enforce minimum security standards for myself and a few coworkers who are currently using Solus. pam_pwquality doesn't meet our requirements, but pam_passwdqc does, and we are using it on other Linux distributions.

Although unclear by their page, pam_passwdqc is included in their more recent release of passwdqc.

It appears that a lot of other distributions do include the package, and it is known for being a powerful and good toolset for password strength, with recent enough releases that it is an active enough project which is unlikely to go away given its inclusion in other distributions.