What phones are on sale on the Fizz platform?

There are all kinds. Android phones as well as iPhones. There are 39 phone models available at the moment, including new and used.

If you cannot see the phones offered by Fizz here: https://fizz.ca/en/plp

You may be able to sign up here: https://community.fizz.ca/questions/2472069-need-phone-need-beta-testers
Or you may have to wait for an invitation from Fizz if you meet the eligibility requirements.