I worked at a security consulting firm that had an 8 GPU password cracking rig. Teams would be able to send it hashes obtained during assessments/red teams and try to discover passwords.

I was not doing that type of work so I'm not sure what type of software was used but I think it had multiple open source programs available.

Like others said, hashcat. Doing pentest/red team stuff, you quite often stumble across password hashes that can do some pretty cool stuff if you can crack them.

Did you know that if you're on a Windows network, random machines all around you will just try to authenticate to you, and disclose the hash of the user on the system? Plug in on a Ethernet jack in the lobby, or conference room, get onto the wifi, compromise any machine on the network and run responder or inveigh, and you just get dumps of user passwords, and if you can crack any of them, its a pretty quick path up to Domain Admin on the network, which then can dump everyone's hashes.

hashcat.