90 heroes for The International it is
Nyx Assassin, Keeper of the Light and Visage were the last three hereos to implemented in the Dota 2 client. They are the heroes 88, 89 and 90 to be included. Only 18 heroes remain, but they will not be included before The International.
"With The International arriving in just over a month, we want to give the competing teams some time to practice with a stable Hero roster, and as few new bugs from us as possible."
Hero development will continue in the background, of course, but releases will be stalled until September.
Unreleased heroes (18 total):
Source: Dota 2 Blog