Here's a start, taken from
these annotations:
Earth 0 - Home of Nix Uotan, Superjudge, at least as of the end of Final Crisis.
Earth 5 - Most likely the home of the robot that Superman trashes on pages 14 and 15 (according to Steel it's a probe from a parallel universe built using weird old technology that shouldn't really work)
Earth 7 - Home of Thunderer
Earth 8 - The home of The Retaliators and Lord Havok
Earth 11 - Home of Aquawoman, Queen of Atlantis
Earth 16 - Home to Bloodwynd and Gypsy, both present in the Hall of Heroes
Earth 23 - Home of Calvin Ellis, Superman
Earth 26 - Home of Captain Carrot
Earth 36 - Home of Red Racer and Flashlight
Earth 41 - Home of Dino Cop and Spore
Earth 42 - The 'Chibi' Earth of the 'Lil Leaguers. The Wonder Woman and Steel of this Earth are both present in the Hall of Heroes
Earth 44 - Home of robot Hawkman
Earth 48 - Home of Lady Quark and Lord Volt