I shall start with a game I'll get soon: Xenoblade Chronicles... and whaddayaknow, there are 7 playable characters in this game !
Jokes aside, "Lucky 7" is one of multiples series I might do for wallpapers. In this case, "Lucky 7" is about making 7 wallpapers based on 7 playable characters. As you might guess, the other series will have different names, depending on the number of characters being used:
2 of a kind Top Tier 4 show 5 alive Cubic Super8 9fold 10Times 11th hour 12 o'clock etc...
Credits go to Nintendo, Monolith Soft and their respective artists