Hmm, tough one...
Here's my list of Officially Released Games, it isn't completed.
Real-Time Strategies:
Dark Ages of Warcraft - Might be slightly imbalanced at times, but it's still one of my favorite ones, helped me get to know the Warcraft lore a lot too.
Coming Of The Horde - Great lore game involving strategy and speed.
Sages of Dustwallow - The terrain layout is nice, and the spawn based effects are just awesome.
Lordaeron Tactics - The mother of all spawn based RTSes with the Warcraft lore, great map with balanced stuff.
Azeroth Wars; Legacy Reborn - Similar to Dark Ages of Warcraft, but set in an earlier time period.
Corruption of Sargeras - The lore is suitable, with a very unique gameplay concept.
World War III: Nuclear Sunrise - This map by Ham_Ham just proves that Warcraft III modern warfare games can rock too.
Legends of the Second War - Great map if you wish to know more about the Second War in Warcraft lore with some excellent models and graphics.
Solar Conquest - Very well made map, it allows you to view "inside the planet" as well as in "space", has a very good game concept.
WoW Risk - A Warcraft lore based Risk game, with almost everything in place.
Risk Devolution - The classic Risk series, played very often.
Hero Arenas:
WoW Arena Allstars - Quite a nice concept, good imitation of WoW based combat.
DotA - I felt I should include this in too, as much as I still would prefer other games, but this is still a nice one.
Diablo III PvP Arena - Definitely a must-try, custom graphics, spells and everything, just neat.
Age Of Myths - Great graphics, unique spells, nice bounty system, this is a pretty fun map to play, I somehow feel that it sure beats DotA 2, Heroes of Newerth or League of Legends any day.
Warlock - A rather popular map with good gameplay.
Role Playing Games:
TKoK Eastern ORPG - I love the concept about it, nice item display and such.
TBR RPG - Well, it has a huge community and it's quite a well made RPG compared to others.
Undead Assault - A shooter RPG with neat graphics and storyline, deserves to be highly rated.
SotDRP - A map meant for hardcore Roleplayers, almost anything is possible in it.
Real Life For Morons - Resembles the Life of a Peasant maps a little, but this one looks way better for Roleplayers.
Thinking Games:
Riddlemaster - Recommended for people who really want to burn their brain.
Parasite - A neat game with a very nice who's-the-killer feel to it.
Mafia - This is just an awesome map, really well made, even without the usual Warcraft III combat styles, this is a thinking game that should be played.
T.M's Riddles - My first riddle map, great for starters and has a hint system too.
Dark Deeds - This is nice for all sorts of people who want a challenge.
Dalaran University - A simple game that's really fun to play at times.
Turn Based Games:
Space Command - My personal favorite in this category, it has an awesome browser-like feel to it and great mechanics without having too much stuff to lag the computer, highly recommended.
Warcraft III Card Game - Well made map with a nice concept, need I say more?
Peppar's Multiplayer Chess - Realistic graphics and the whole chess concept is there, great map.
Azeroth Poker - Nicely triggered map of Poker, neat and fun at the same time.
Tower Defense:
Element TD - An awesome Tower Defense with a great style of playing, I also find the Ronald Finale rather cute.
Distilled Water TD - Made by a fellow Hive Workshop member, it is quite fun.
Monopoly TD - One of the best Tower Defense maps I've ever seen, definitely should be played.
Gem TD - A pretty nice map with a good concept to it.
You TD - A bit of a different kind of Tower Defense compared to the others, it gives an RPG feel as well as a feel that your towers are like 'Heroes', comes with an XP system too.
Legion TD - A competitive TD about skill and speed.
Miscellaneous Games:
Uther Party - Very popular map with a jumbo pack filled with different types of games.
Pyramid Escape - An Uther Party styled map, with a little twist.
Soldiers - Quite an awesome 2D map I have to say, with modern warfare theme.
101 Rounds - A dodging game with custom music, concept and much more, really addictive and tricky at times.
Cannon Commander - A Two-Player map with a lot of custom imports, overall I think it's extremely cool and adorable.
I'll include more later!