Capcom of Japan has released several Rockman games for mobile phones in Japan based on the various series within the franchise. The vast majority of them have never seen the light outside of Japan, though a few, such as Rockman Space Rescue and Mega Man Rocket Christmas, were ported for overseas cell phones. They are typically inexpensive ports or unique mini-game style releases that I predict are difficult to play, given the cell phone's not-so-dedicated gaming interface. Here is a basic list of the Mega Man titles released for Japanese mobile phones:
Kobun Assembly (2001)
Kobun Flies? (2001)
Tide Coming Kobun (2001)
Watch Kobun (2001)
Rockman DASH 15 Panel (2002)
Mega Man (2003)
Mega Man Rocket Christmas (2003)
Rockman Bug Sweeper (2003)
Rockman DASH Golf (2003)
Rockman Panic Fire (2003)
Rockman Space Rescue (2003)
Rockman Slot (2003)
Jump! Rockman (2004)
Rockman 3 Dr. Wily no Saigo!? (2004)
RockMan.EXE: Phantom of Network (2004)
Rockman GP (2004)
Rockman Pinball (2004)
Rockman 4 Arata Naru Yabo!! (2005)
Rockman 5 Blues no Wana?! (2006)
RockMan.EXE: Legend of Network (2006)
Mega Man 2 (2007)
Rockman 6 Shijo Saidai no Tatakai!! (2007)
Rockman X (2007)
Rockman DASH - Grand 5 Island Adventure (2008)
Rockman X2 (2009)
Intuition! Rockman (2010)
Megaman Rush Marine (2010)
Rockman Tennis (2010)
Rockman X3 (2010)
Rockman Diver (2011)
Rockman the Puzzle Battle (2011)
Rockman's Sprite Logic (2011)
Yes, really. Mega Man Rocket Christmas.