1 - Random.org
Random.org has been one of my favorite sites for a long time. It uses atmospheric noise to generate its randomness which is much better than the logical pseudo-random generators used by many sites and service.
You choose the password parameters you need and it generates wonderfully random passwords to use with your password manager of choice.
2 - Symantec Identity Safe
Symantec has been a mainstay of the security market since the 90s and they bought a company called PCTools (and its Secure Password Generator). As a PC Tool vendor, they will try to make you download their privacy tools but I wouldn't recommend their password vault.
Use the password generator on the right side of their site to generate high quality complicated passwords with the required complications. As an example, the above complications generated this password for me : dr-cr+wreF5p.
3 - Wolfram Alpha
Wolfram Alpha is a powerful knowledge engine created by the brainiacs behind mathematica, It is a superb tool I use regularly for problem solving but it also generate random passwords. Head over to their knowledge engine and enter Generate Strong Password. Then press the equal sign.
Then choose the complications you want and press the equal sign again to generate you password.
then it generates your wonderful password
you press on Plaintext and copy it into your favorite website or password manager.
4 - Lastpass password generator
My 2 favourite password managers are Lastpass and 1Password. Both have the capbility to generate strong passwords and you should use that functionality if you have those those. Considering most of Lastpass is now free to use, you really have no excuse.
But Lastpass also offers a web based secure password generator which is clean, easy to use and efficient.
When you scoll up on that page after choosing your complications, you get a wonderfully generated password of your can click the button and have another one created for you.
5 - GRC Ultra High Security Password Generator
GRC is the home of Gibson Research Corporation. It is owned by Steve Gibson the Grand Poobah of internet security. He found the first spyware and wrote the first anti-spyware app. He is considered one of the most prominent security professionals and makes tones of tools available on his site.
His site generates perfectly random long complex 64/63 character passwords and he then explains why his passwords are high quality. If you are interested in geeking out, its a wonderful read.