d20 or d100 system. a group of beings travelling through time.
playable races include humans, time lords, silurians, sontarans, etc.
playable classes include soldiers, time agents, scientists.
now this won’t leave me alone for days.
Someone else mentioned the FASA and Cubicle 7 Doctor Who systems. There is also the 90’s TIMELORD system. Which is available for free download from the original creator.