I find the American ones tend to be very boring. I once tried to get into the John Wayne films, but after 2 or 3 I was too bored to continue watching those.
Last ones I watched were The Magnificent 7, which was good, and How the West was Won, which was awful (especially for the great cast they had assembled - the biggest waste of a great cast I’ve seen since the atrocious “White, Yellow, Black” abomination Corbucci committed in 1975).
Eastwoods Westerns were good, but apart from those, I haven’t seen many good ones. I guess this was in large part thanks to the production code in force till 1968 (which imposed strict moral restrictions on what could be depicted in films), which was abolished due to an Italian film BTW (I think it was one by Rosselini - not a Western surprisingly).
I have The Wild Bunch, Tombstone and Unforgiven on my watchlist. Any others worth watching?
As someone who also finds most John Wayne westerns quite boring, I will ditto Seb and recommend Anthony Mann’s westerns, especially the ones with Jimmy Stuart
I love John Wayne, but if you’re looking for something along the lines of Tombstone and the Wild Bunch - which I also love - and assuming you’ve seen the Eastwood ones (Josey Wales, Sister Sara ect.) I’d say Pat Garrett and Billy the Kid by Peckinpah, Butch and Sundance, and probably The Life and Times of Judge Roy Bean for its quirkiness. Maybe The Long Riders would be up your street, too.
I would recommend the book Renegade Westerns, which lists approximate 100 westerns from 1940s to present day of American Westerns which are not considered as traditional American westerns or heroes are not wearing white hats! Starting with the 1943 film Ox-Bow incident through to 2017 Hostiles. Other movies included in the book are 1956 Last Hunt, 1954 Vera Cruz, 1966 The Professionals and 1969 Wild Bunch to name a few!