A massive chart courtesy of PC Gamer that shows "Blizzard's DNA" by tracing the path some of their employees have taken between Blizzard games and moving on to form or work at other companies.

This is far from a complete list; there are dozens of employees who played a key role on D2 and D2X not listed, quite a few of whom moved on to Flagship Studios. The same is true of the other Blizzard games as well, but while far from encyclopedic, the list provides a nice overview of the connections between the games and their makers.