Personally:
1959
X-Men First Class: The High Hand
1962
X-Men: First Class
X-Men Origins: Wolverine
X-Men
X-Men 2: Wolverine
X-Men 2: Nightcrawler
X2: X-Men United
2006
X-Men: The Last Stand
2013
The Wolverine: Unleashed Extended Edition
2017
Trask Industries: Your Future
The Bent Bullet: JFK and the Mutant Conspiracy
25 Moments in the Struggle between X-Men and Humans
2023/1973
X-Men: Days of Future Past
1883
X-Men: Apocalypse
2015
Fant4stic
2020
Deadpool
2021
No Good Deed
Deadpool 2: Super Duper $@%!#& Cut
2026
Laura.mov
2029
Logan
Reasoning:
X-Men: Days of Future Past: The Rogue Cut is non-canon. End of story.
Fant4stic is presumably non-canon but the team was going to be in Deadpool 2, based on a concept artist, so the team can be apart of the universe if they so wish.
Wade Wilson may be 70 years old, but in Deadpool, the two year flashback had a comment about the year of the dog.
Valentines Day
Year of the Dog
International Women's Day
The year of the dog scene was between Valentines Day and International Women's Day so it's between them in terms of timeline.
1994 = February 10
This doesn't work because it's before Valentines day.
2006 = January 29
This doesn't work because it's before Valentines day.
2018 = February 2018
2 days after Valentines Day. Works perfectly.
Deadpool's age needs to be ignored.
Colossus needs to be ignored.
X-Men cameo needs to be ignored.
Either that or they just really wanted to do it doggy style. Ew.
Either way:
X-Men: First Class
X-Men Origins: Wolverine
X-Men
X2: X-Men United
X-Men: The Last Stand
The Wolverine: Unleashed Extended Edition
X-Men: Days of Future Past
X-Men: Apocalypse
Fant4stic (non-canon)
Deadpool
Deadpool 2: Super Duper $@%!#& Cut
Logan