As a follow-up to my last post about 1d6 based games, here's one commercial game I missed. Deep7's 1PG, or 1-page, RPG is a rules-lite game where, as you might guess, all the rules fit on one page. The basic mechanic is a 1d6 roll under, where a roll of one is an automatic sucess and a roll of six is an automatic failure. Despite being so rules-lite it's a very well supported game, with rules covering just about any genre you can imagine, like anime with Exosuit A-OK, space opera with Star Legion, and of course fantasy with Broadsword.
I'm not sure I like the idea of characters automatically failing 16.7% of the time. That seems a little high to me. RuneQuest got into Murphy's Rules for less than that. But maybe there are some other rules that modify that in some of the books. In any case, it's it's a 1d6 game that's going strong.