Those were called "data caps". Here in suburban Sacramento we haven't had them in years---been unlimited since at least 2015--- and, every 18 months or so, Comcast tells me they can upgrade my internet speed to mega-giga-whatever and knock five bucks off what I've been paying for just giga-whatever.
And son of a gun, here's an article showing who still has them and who doesn't written eight days ago:
Find out which internet providers have strict data caps, which charge extra for unlimited data every month, and which offer unlimited data on every plan.
www.highspeedinternet.com