Oh well, I updated my personal list.
1- X-Men: Days of Future Past (2014) - brilliant sci-fi movie
2- X-Men: Apocalypse (2016) - epic superhero movie, the most X-Men-ish so far
3- X2: X-Men United (2003)
4- X-Men: First Class (2011)
5- Dark Phoenix (2019) - second half could have been much better, overall great
6- X-Men: The Last Stand (2006) - brilliant superhero movie, very bleak
7- The New Mutants (2020) - fascinating, entertaining and well-crafted
8- Logan (2017)
9- The Wolverine (2013)
10- X-Men (2000) - a modern classic which paved the way to the modern superhero genre
11- Deadpool 2 (2018)
12- X-Men Origins: Wolverine (2009) - fun and entertaining
13- Deadpool (2016) - still a great movie