Speedtest.net to Navasota (which every ISP now knows it needs to fake):
fast.com test (to netflix, to check for throttling, but ISPs are getting wise now)
Speedof.me (which most ISPs haven't figured out they need to fake out yet)
Testmy.net results, which are similarly not yet in their fakery sights
DSLreports.com/speedtest , which used to be a go-to, but looks like it's as unreliable as speedtest.net now.
And just for giggles, here's the google Stadia speed test to see if your connection is good enough to play on Stadia -
Downloads from steam seem to vary from moment to moment and are probably more steam's fault than anything, but I usually get 100-200mbit and only very occasionally 400ish mbit