This is the order of my X-Men Blu-Ray collection. I use three shelves.
SHELF 1 - Original Trilogy:
X-Men Origins: Wolverine
X-Men
X2
X-Men: The Last Stand
Logan
SHELF 2 - Beginnings Universe:
X-Men: First Class
The Wolverine - Unleashed Extended Edition
X-Men: Days of Future Past
X-Men: Days of Future Past - The Rogue Cut
X-Men: Apocalypse
Dark Phoenix (not bought yet, of course)
SHELF 3 - Alternate Dimensions:
Deadpool
Deadpool 2
Legion Box-Set
The Gifted Box-Set