Looking at the number of bills introduced right at the start of the new congress I'm under the impression that many of these are introduced only so the congressperson can go back and say "I introduced a bill to do ____" and brag about it.
It would be interesting to data mine these and see how effective certain legislators are at just introducing bills compared to actually getting them passed.
Govtrack tracks this and compiles report cards that (mostly) reveal what you're looking for, e.g., its reports on Bills Introduced, Bills Out of Committee, and Laws Enacted [1]. The 2020 report cards should come out sometime this month.
