The titles were described as new intellectual properties, which would exclude new entries in franchises like Rock Band or Dance Central.
"Some of them are music games. Some of them are not full-on rhythm action games," Harmonix's director of communications and brand management John Drake said on the Harmonix podcast.
"Some of them are brand new things that we created from our guts and brains here at Harmonix. Some of them are sort of like things we're explaining the universe of."
Harmonix currently has 20 job openings, including positions for level and narrative designers to work on an "innovative motion-gaming IP on next-generation hardware".
The next game from the studio will be Rock Band Blitz, a downloadable rhythm game spin-off for the series using a standard controller to switch between different instrument tracks.
Rock Band Blitz will release on XBLA and PSN this summer.
Watch the announcement trailer for Rock Band Blitz below: