DOTA 2 Official Heroes

Confirmed by Valve

• Bloodseeker
• Drow Ranger
• Lina
• Morphling

IGN sneak peek

• Axe
• Beastmaster
• Riki
• Sven
• Tidehunter

SteamPowered sneak peek

• Lich
• Vengeful Spirit
• Death Prophet

DotallyRad 

• Furion
• Windrunner
• Necrolyte
• Sniper
• Dark Seer
• Slardar
• Earthshaker
• Kunkka
• Pudge (Butcher)
• Nevermore
• Enchantress
• Leshrac
• Tinker
• Witch Doctor
• Atropos
• Warlock
• Viper
• Rattletrap (Clockwerk Goblin)

Dota-Two 

• Razor
• Pugna
• Zeus
• Faceless Void
• Shadow Shaman
• Crystal Maiden
• Shadow Priest
• Storm Spirit
• Venomancer
• Dragon Knight
• Enigma
• Bounty Hunter
• Moon Rider
• Omniknight
• Queen of Pain
• Centaur
• Ursa
• Skeleton King
• Tiny
• Mirana
• Puck
• Yurnero

Team Fortress 2

• Ancient Apparition
• Doom Bringer
• Spectre
• Antimage