CriticalDice
CriticalDice is a virtual "table" that can be accessed and modified by multiple people at once. It is based on Javascript and a Peer2Peer networking model.
Try the prototype out: api-beast.github.io/CriticalDice
Rather than trying to emulate the system that tabletop games use, it tries to emulate the medium they are played on. Many virtual objects can be placed and interacted with on the table, like tokens, dice, playing cards or notes.