Adventure Construction Set (8-bit home computers):
The first decently-featured RPG construction tool for consumer use. Interesting levelless, skill-based, increase-through-use design was far ahead of its time. Unique method of scripting. Even contains a random adventure generator, an amazing feat on a 8-bit computer.
The Magic Candle (early computers):
A cult favorite. You could drop characters off in various places in the world, and while there they could work at their professions and contribute the money towards the quest!
The Bard's Tale (series, available for many older computers):
A surprisingly popular RPG series. In basic design it's very similar to Wizardry, but with even more devious mazes and mapping puzzles. An incredible challenge to complete.
The Bard's Tale Construction Kit (DOS):
Essentially a Wizardry game creation tool.
Infinite Adventures (DOS):
And this is a Gold Box AD&D game creation tool.
AD&D Black Box series (DOS):
Stuck in the shadow of the superlative Gold Box games. Many of these had big bug issues on first release, and this was the days before patches could be downloaded from websites. Still, some of these games, when patched, are quite cool. They hit many of TSR's more niche campaign settings, like Al-Qadim, Dark Sun, Ravenloft and Spelljammer.
Eye of the Beholder (PC, Amiga, SNES):
Possibly the height of the AD&D Black Box series, a Wizardry-like dungeon crawl bound by AD&D 2E rules.
Dungeon Hack (PC):
A Black Box game running off the Eye of the Beholder engine, but with random levels. The closest thing to an official D&D roguelike we'll probably ever see. Tremendously flexible in its dungeon construction module, allowing the player to set up his adventure nearly any way he could want.
A sadly forgotten, atmospheric game for the Amiga, a system that was home to a number of interesting, forgotten RPGs.
Dungeon Master (Amiga, PC, SNES):
Brought a greater degree of real-time play to Wizardry.
Isometric turn-based tactical combat, but in the future in a fight with aliens. Another cult favorite.
Grandia (Saturn & PlayStation):
One of the best-characterized JRPG stories of all time. Speaking as someone who hates most RPG stories: this one's great. If only Final Fantasy games had characters like this.
Angband (most current platforms, open source):
Perhaps the most modable role-playing game ever constructed. Yes, even more than Neverwinter Nights. It's well-laid-out source code, the work of prior maintainer Ben Harrison, has made it, by far, the roguelike with the most variants.
Dungeon Crawl (most current computer platforms including Wii homebrew, open source):
A superbly-balanced game.
ADOM (Windows , Mac, Linux):
There are only three games that could possibly aspire to Nethack's level of completeness and depth. This is #2.
Dwarf Fortress (adventurer mode) (Windows, Linux):
This is #3.
Planescape Torment (Windows):
Based off the Baldur's Gate engine. There are people who consider this the finest CRPG ever made. While my heart belongs to Nethack, it is a damn fine game.
Ogre Battle (SNES/Super Famicom, PlayStation, N64):
A unique series of three games. Known for high difficulty (in the first two games at least), highly engaging real time strategy play, many secrets and its many hard-to-get endings. Does some things that no other series has made work.
Tactics Ogre (PlayStation, GBA):
The first game was a predecessor to Final Fantasy Tactics. Did much to further the cause of the isometric turn-based RPG strategy genre. Nippon Ichi's popular tactics games owe this series much.
Skies of Arcadia (Dreamcast, Gamecube):
A sorely-neglected RPG set in a world of flying airships and pirates. Its exploration mechanics are wonderful and bring an aspect of -- dare I say it? -- skill to the game. Fun just to fly around in, and has many hidden wonders to find. The best RPG on the Dreamcast.
Odin Sphere (PS2):
Partly action game and partly RPG, has amazing 2D animation and some unique sim elements based on growing seeds that produce various kinds of fruit (some of it fairly strange, like ambulatory sheep). These plants need the souls of defeated enemies to grow, so the player must plant early in a battle to enable the seed to mature before the fight can end.
Neverwinter Nights (AOL):
Essentially a MMORPG Gold Box AD&D game! Sadly gone now.
Neverwinter Nights (BioWare)
Contains a single-player campaign of some note, but best remembered for its amazing toolset, essentially making it into a generalized AD&D 3E CRPG creator and client, even providing for DM functions.
- Hardcore Gaming 101
- The book Dungeons & Desktops, written by Matt Barton
- The original Dungeons & Dragons boxed set, written by Gary Gygax and Dave Arneson. Additionally, early issues of TSR's newsletter The Strategic Review and Dragon Magazine.