Information in the game database is updated periodically. Below, you'll find that information compiled as pertains to Treasure. The company may be involved as a publisher, developer or both.
Advance Guardian Heroes [September 14, 2004]
Astro Boy: Omega Factor [August 18, 2004]
Gunstar Super Heroes [October 25, 2005]
Hajime no Ippo: THE FIGHTING! [December 12, 2002]
Tiny Toon Adventures: Scary Dreams [July 5, 2002]
Dynamite Headdy 
Alien Soldier [unknown]
Dynamite Headdy [September, 1994]
Gunstar Heroes [September 9, 1993]
Light Crusader [May 25, 1995]
McDonald's Treasure Land Adventure [December, 1993]
Yuu Yuu Hakusho: Makyo Toitsusen [September 30, 1994]
Dynamite Headdy [unknown]
Ikaruga [April 9, 2008]
There are numerous companies in the industry, and their names change like the weather. The information above is not particular about the finer details. Acquisitions are common, so companies with no recent listings may still be developing games under a new name. For example, DMA Design currently has a Rockstar name. Do you know of a title that is not listed above but should be? Be sure and let a staff member know. You can contact staff if you click here.