I remember being 9 years old, my cousin showed me this awesome game. (He was playing it because of DotA Allstars then). I fell in love with the game since then. I remember playing Monolith day and night with my friends, DotA, many Castle Defense mods and many others. With each patch released, the game evolved even better. The program called World Editor is what led the modding magic touch us all. We all became "game designers" with the mods made by us. I would like to mention some extraordinary people that created awesome games for Warcraft 3 (No, I cannot call them mods, since they are too good) :
1)
@SpasMaster - Sunken City (The best by far! The best I say, RPG dungeon crawling game with highly advanced mechanisms, cool heroes, addicting gameplay that feels like the first time everytime you replay it. Recently I'm playing it a lot, and I advise you all to do the same).
2)
@Wa666r - God of custom races and altered melee maps. I and my friends adore you and your work. You managed to create extraordinary races with suitable synergies and various mechanisms. Thumbs up!
3)
@Rufus - Warden (Innovatively and very enjoyable game. Warden has a unique system which allows the player to control Shalis (the Warden) using the arrow keys. The environments and puzzles of each level in the Warden game are purely amazing. You feel like you are playing Prince of Persia in Warcraft 3. Believe it!
4)
@Zwiebelchen - Gaia's Retaliation (Did you ever want to play something like World of Warcraft in Warcraft 3? Well, now you have that possibility! This RPG is extremely cool and in my opinion it will never have competition. The regions in it are amazing, characters very suitable and gameplay experience assured to a high level!
5)
@Alxen345 - I know what you might say, "He's promoting an AoS like DotA. Waw" . Believe it or not, Dungeon of Warriors is nothing like DotA. Different heroes, different items, different synergies in teamplay, different terrain (much more better than the one from DotA). DotA 1 is a relic for Warcraft 3. The game needs a new AoS that will succeed it.
6)
@MoCo - Dwarven Monster Slayers (Are you a fan of action? DMS is the right choice for you. A unique RPG survival with a team of unique dwarves controlled by players. You'll have fun for sure! Also, this one is turning into a standalone game.
There are also many other modders, but I listed my favorite ones.