Divine Right: The Adventures of Max Faraday.
Kingdom Come
The Longbow Hunters
Superman: For All Seasons (Loeb and Sale)
Omg this is so hard!!! But I’m gonna have to go with Grayson omnibus since there’s is no Dixon run omnibus and I can’t choose just one of the volumes.
WOW, I owned a hardcover of that a long time ago. Very sad book. Dini really bared his soul in it.
Arkham Asylum: Living Hell
Crisis on Infinite Earths Absolute Edition
Swamp Thing: The Anatomy Lesson
That’s more of a single issue, but I’ll upgrade that to Saga of the Swamp Thing: Book One.
Thanks, that’s what I was thinking, but I knew that the full arc was called The Anatomy Lesson. So I went with that
Happy Birthday
Thank you! 
Justice by Alex Ross and Jim Krueger
If this counts, JLA/Avengers. If it doesn’t, I have backup but won’t break the rules.