I guess there’s no other way than to just check them out.
I got a generic, dirt cheap one, and it works great with the Fairphone 2 battery.
Edit: For the people following the link (what was I thinking 
) … the charger isn’t available anymore where I got it back then, but it is still widely available on eBay, just search for “universal battery charger” and you should see multiple sellers for basically the same charger.