There are many titles I wish I had read; I have bookcases filled with unread and partially read volumes. But here are some that are high on my list:
Untouched by Human Hands: The Last Dangerous Visions, by Robert Sheckley and Harlan Ellison. Ellison’s famous epic struggle to get his last Dangerous Visions anthology out is assisted by Sheckley.
All the Myriad Ways: Of Man and Monsters, Heroes and Horrors, Parsecs and Parables, Nightmares and Geezenstacks, Ice and Iron, Digits and Dastards, Murder and Magic, Ape and Essence, Fancies and Goodnights, Alchemy and Academe, Foundation and Empire, Visions and Ventures, Time and the Stars, by Larry Niven, William Tenn, Fritz Leiber, Robert Silverberg, Fredric Brown, William Tucker, Frederik Pohl, Randall Garrett, Aldous Huxley, John Collier, Anne McCaffrey, Isaac Asimov, Theodore Sturgeon and Poul Anderson. A galaxy and time-spanning story of nouns smashed together into subjects.
“Repent, Harlequin!” Said the Ticktockman, Or All the Seas With Oysters, formed of Mist, and Grass, and Sand, and ruled by the Queen of Air and Darkness, will carry you Adrift Just Off the Islets of Langerhans: Latitude 38º54’N, Longitude 77º00’13″W, where you may watch The Dance of the Changer and the Three, and learn that Love is the Plan the Plan is Death, and that The Ones Who Walk Away from Omelas must confront The Doors of His Face, the Lamps of His Mouth, never to discover that Time Considered as a Helix of Semi-Precious Stones is the Good News from the Vatican, by Harlan Ellison, Avram Davidson, Vonda N. McIntyre, Poul Anderson, Terry Carr, James Tiptree Jr., Usula K. LeGuin, Roger Zelazny, Samuel R. Delany, and Robert Silverberg. This surprisingly thin science fiction-fantasy mix is essentially a fleshed-out expansion of the title.