Please, no gratuitous criticism or Fox-bashing. This is for the Marvel fans who enjoyed and loved the movies.
The Original Timeline
5000 BC: En Sabah Nur arrives in Egypt with his Four Horsemen (DOFP post-credits scene).
3600 BC: En Sabah Nur is defeated.
1832: James Howlett is born.
1845: Victor Logan and James Howlett escape from home.
1932: Charles Xavier is born.
1934: Raven Darkhölme is born.
1938: William Stryker Jr. is born.
1944: Erik Magnus Lehnsherr hold at the concentration camp.
1945: James Logan operates in Japan.
1953: Jason Stryker is born.
1959: Ororo Munroe is born.
1962: X-Men: First Class
1963: Magneto is captured. The Brotherhood of Mutants disband.
1965: Emma Silverfox is born, a clone of Emma Frost created by Project WideAwake/Essex Corp.
1968: Mortimer Toynbee Jr. is born, son of the first Toad.
1972: Sean Cassidy II is born, a clone created by Project WideAwake/Essex Corp.
1973: James Logan deserts New York and embarks on a final war tour. James Logan and Victor Creed are then recruited by Stryker in Vietnam. Meanwhile, Mystique kills Bolivar Trask.
1975: Peter Maximoff II is born, a clone created by Project WideAwake/Essex Corp. Affected by accelerated growth.
1977: After years, James Logan leaves Team X. Jason Stryker is cryogenized.
1978: Magneto escapes (or is freed) and finally joins Xavier. They start working together again. Xavier takes a new serum which doesn't inhibit his mutant powers, but brings several collateral effects on the long term.
1979: "The Last Stand" Prologue. Xavier and Magneto recruit Jean Grey.
1983: X-Men Origins: Wolverine. The Weapon X Project occurs.
1990: Warren Worthington III's childhood flashback.
1991: The X-Men finally reform - Cyclops, Storm, Jean Grey/Marvel Girl, Beast, Havok, Emma Silverfox/White Queen.
1996: Beast, Havok and Emma Silverfox leave the team, and the remaining X-Men temporarily stop their activity.
1999: X-Men ("Future time" from a First Class perspective). Wolverine joins the X-Men.
1999: X2
2000: X-Men: The Last Stand
2001: Magneto regains his powers.
2002: The X-Men fights Magneto again, as hinted by Wolverine in DOFP.
2007: The X-Men disband. Logan disappears.
2008: The Wolverine
2010: "The Wolverine" Post-Credits sequence.
2023: The DOFP Bleak Future.
The New Timeline
5000 BC: En Sabah Nur arrives in Egypt with his Four Horsemen (DOFP post-credits scene).
3600 BC: En Sabah Nur is defeated.
1832: James Howlett is born.
1845: Victor Logan and James Howlett escape from home.
1932: Charles Xavier is born.
1934: Raven Darkhölme is born.
1938: William Stryker Jr. is born.
1944: Erik Magnus Lehnsherr hold at the concentration camp.
1945: James Logan operates in Japan.
1953: Jason Stryker is born.
1959: Ororo Munroe is born.
1962: X-Men: First Class
1963: Magneto is captured. The Brotherhood of Mutants disband.
1965: Emma Silverfox is born, a clone of Emma Frost created by Project WideAwake/Essex Corp.
1968: Mortimer Toynbee Jr. is born, son of the first Toad.
1972: Sean Cassidy II is born, a clone created by Project WideAwake/Essex Corp.
1973: X-Men: Days of Future Past
1974: Mystique frees Logan.
1975: Xavier adopts Jean Grey some time after the car crash.
1982: The British mutant Archangel (not Warren) operates in Germany. Logan is captured by Stryker.
1983: X-Men: Apocalypse. The X-Men are reformed - Cyclops, Mystique, J. Grey/Phoenix, Beast, Nightcrawler, Quicksilver, M. MacTaggert.
1992: Dark Phoenix
1997: Emma Silverfox/Frost quits Russel Tresh's facility and project.
2002: Generation X. Featuring Emma Silverfox/Frost and Banshee II.
2008: The New Mutants.
2023: The DOFP New Future.
Alternate Universes:
The Rogue Cut (2023)
Deadpool (2016-2018)
Legion
Logan (2029)
The Gifted
Some dimensions Deadpool visited at the end of "Deadpool 2".