Don’t remember the tool, maybe someone here does, but there’s some web service out there that boasts a “no storage” approach. You provide some URI and some other value (maybe username) and it makes a password for you, but it’s always the same for a given combination. Basically it’s a purely functional generator.
Downside would be forgetting a minor detail (Did it end with a slash or not? What was the username?) or the site going down. You can achieve the same thing yourself with a hash calculator but those passwords are a bitch to type in.