I use password-store by ZX2C4 as my password manager of choice.
I also have been following Troy Hunt's project haveibeenpwned.com, this is a great tool that has received lots of praise for shining a light on just on likley it is that your credentials (emails or passwords) have already been compromised. Addionally he provides an API for checking your password aginst a database of known breached passwords.
Here is a short write-up about how 1Password.org has used this API to discourage the re-use of a known password.
I decided that I needed this functionality as well, so in following the footsteps of others I built an extension for password-store that you can use to check your password using the Have I Been Pwned: API V2.