In a blog post recently, Ubisoft revealed the games they will be showing off at E3, and they are as follows:

Assassin's Creed Unity: Taking place during the turmoil and horror of the French Revolution, the Templars and Assassins find themselves continually embroiled in their century-spanning conflict.

Far Cry 4: Moving from the lush vistas of islands of the previous three games to the mountainous country of the Himalayas, you find yourself struggling against a maniacal, despotic, self-appointed ruler.
The Division: A Tom Clancy game in name only, you play as part of a sleeper cell of agents in New York after the city has been thrown into lockdown by a bioterror attack. Revealed as a surprise at last year's E3, and now delayed to 2015, it should, regardless, be interesting to see where the game has gone since then.

The Crew: An open world driving game with RPG elements, you will be able to build a "crew" of friends to race against time trials and other races as well.

Ubisoft ends the post by saying that many other games will be available on the showfloor. While there's no indication of any surprise reveals, as was the case for last year, it's impossible to rule anything out. With Aisha Tyler returning to host the conference again, we shall see just how far Ubisoft has come in the year since 2013's E3.