here's a List of the Content of the Case Files
Case Files 01: 'The Robot Wars'
Case Files 02: 'The Cursed Earth'/'The Day the Law Died' ('Judge Cal' saga)
Case Files 04: 'The Judge Child Quest'
Case Files 05: 'Block Mania'/'The Apocalypse War'/Hot Dog Run
Case Files 08: 'City of the Damned'
Case Files 11: 'Oz'
Case Files 14: 'Necropolis'
Case Files 17: 'Judgement Day'
Case Files 18-19: 'Mechanismo'/'Mechanismo Returns'/'Body Count'
Case Files 19: 'Inferno'
Case Files 21: 'Wilderlands'/'Tenth Planet'
Other 'important'/notable Judge Dredd stories', from a continuity point of view:
Case Files 01: 'The Return of Rico' (first appearance of Rico), 'fhe First Lunar Olympics'/'War' (First appearance of Sov Block)
Case Files 03: 'Judge Death' (first appearance of Judge Anderson, Judge Death)
Case Files 05: 'Judge Death Lives!', 'The Fink' (first appearance of Fink Angel), 'Pirates of the Black Atlantic', 'Unamerican Grafitti' (first appearance of Chopper)
Case Files 06: Various post-Apocalypse War stories, including 'Destiny's Angels'
Case Files 07: 'Cry of the Werewolf', 'The Graveyard Shift' (two fan-favourite stories, especially with hardcore Dreddheads)
Case Files 08: 'Dredd Angel', 'A Question of Judgement'/'An Error of Judgement'/'A Case For Treatment'
Case Files 09: 'The Midnight Surfer', 'The Warlord'/'A Chief Judge Resigns', 'Letter From a Democrat'
Case Files 10: 'The Taxidermist' (first appearance of Jacob Sardini), 'Atlantis' (first appearance of Brit-Cit)
Case Files 12: 'Hitman', 'Bloodline' (first appearance of Kraken), 'Our Man in Hondo' (first appearance of Hondo-Cit)
Case Files 13: 'Young Giant' (first appearance of Judge Giant Jr), 'The Shooting Match', 'A Letter To Judge Dredd'
Case Files 15: 'Nightmares', 'Death Aid'/'Emerald Isle' (first Dredd strips written by Garth Ennis), 'Return of the King'
Case Files 16: 'The Devil You Know'/'Twilights Last Gleaming'
Case Files 20: 'Bury My Knee at Wounded Heart', 'Giant'
Case Files 21: 'Casualties of War' (Rogue Trooper crossover)