Quarterback debates are the foundation of modern society, and maybe even the impetus for the creation of spoken and written language. We may never truly know if Joe Flacco is elite, but we do know we're all better for having argued about it.
Unfortunately, fantasy-football QB debates tend to be a bit less contentious, lacking the 'stats vs. rings' dimension that once made it seem reasonable to compare Flacco to Matt Ryan. By no means will I go out of my way to be controversial in the rankings below, but I do strongly encourage disagreement and all other forms of positive or negative feedback.
Keep in mind that the rankings are intended for 2020 redraft leagues, assuming Yahoo/ESPN standard scoring where 25 passing yards equate to one point and a passing TD counts for four. Personally, I prefer 20/6 scoring to boost the fantasy value of the position closer to its real-life value, but we'll go with what the majority of people are using, rather than what I think they should be using (a noble concession, no doubt).
The fantasy leagues I have in mind for these rankings are those with 10-to-14 teams and one QB spot. It's usually feasible to stream the position week-to-week in these leagues, which means draft picks should focus on upside more so than job security or floor. For example, I'd rather use a late-round pick on Tyrod Taylor than Derek Carr, knowing I can find reliable mediocrity — and probably even