Today, Microsoft's Major Nelson blog announced that Mega Man Legacy Collection 2 is now available to pre-order digitally for $19.99 on the Xbox One. The suite of games will be made available on August 8, but you can pre-download it for your console now. The physical versions of the game have been available to pre-order for some time.
While the original Legacy Collection contained the first six games from the Mega Man series, this one contains the next four. Two of those, including Mega Man 9 and Mega Man 10 were originally released for the Xbox 360, and are already available via the Xbox One Backward Compatibility program for $9.99 each, so you're pretty much getting two additional games for free.
Mega Man 8, however, was released almost 12 years prior to its successor in 1996, and is currently only available for PlayStation, PlayStation 2, Sega Saturn, and GameCube. Its predecessor, Mega Man 7, was released for the Super NES in 1995, so we can see that Legacy Collection 2 spans throughout four generations of gaming.