So DC hasn't forgotten about the 30th anniversary of Hellblazer, as they'll be putting out a celebratory hardcover collection later this year, just in time for Halloween.
However, with 300 issues, there's only so much you can include in one collection. The official solicit is:
Saga of the Swamp Thing #37 (where it all began)
Hellblazer #11 (Newcastle)
Hellblazer #27 (Hold Me)
Hellblazer #41 (Dangerous Habits Part One)
Hellblazer #63 (Forty)
Hellblazer #120 (Desperately Seeking Something)
Hellblazer #146 (Hard Time Part One)
Hellblazer #229 (collected here if you don't want to buy the upcoming reprint of Denise Mina's run to have all of Hellblazer in trade)
Hellblazer #240 (The Laughing Magician Part One)
What would you put in your Hellblazer 30th Collection?
For my personal selection, I'd try to stick to stories that function as stand-alones, leaving out Part Ones of longer story arcs:
Delano: Hellblazer #1&2, Newcastle, Mourning of the Magician, Dead Boy's Heart
Ennis: The Diary of Danny Drake, End of the Line, Forty - because you can't have a Hellblazer 30th Celebration and leave out Mange!, maybe the break-up issue
Jenkins: #100 - Sins of the Father, #119 - Undertow, and ofc the aforementioned 120
Ellis: Telling Tales
Azzarello: If I had to acknowledge Azzarello... maybe Lapdogs & Englishman? Or just to give the imaginary readers of this imaginary collection a big WTF, the issue where John gets a hooker and scams old ladies at bingo.
Carey: The Game of Cat & Mouse, Event Horizon, The Gift
Post-Carey: Perhaps Diggle's Vatican two-parter, or Ravenscar Casino
Gaiman, Morrison, and John Smith's fill-ins would make the cut as well.
(kind of surprised two of the bigger-name writers who worked on Hellblazer, Morrison and Ellis, are nowhere to be seen in the actual collection)