Any children of Cheryl and Bob in Camikaze Kid (their existence erased after Sam prevented their marriage)
Roget in Honeymoon Express (killed by Sam)
Any children of Charlie and Lanore in The Americanization of Machiko (their existence erased after Sam prevented their marriage)
Pete in Blind Faith (after being caught as the serial strangler, may have received the death penalty)
The French Woman from Blind Faith (Al seemed to have no record of her dying or it would have been reported to Sam so he could prevent it, so may not have happened in the original history)
Jimmy in A Portrait for Troian (drowned in the lake after Sam pushed him in to prevent Jimmy from killing Troian)
Nick in Her Charm (killed by Sam)
Joseph Washake in Freedom (his time of death was sped up when Sam took him to the reservation to die with dignity, instead of being kept alive at hospital)
Stephanie in Goodnight Dear Heart (catching her as the killer may have resulted in her receiving the death penalty. Unlikely though, as there is a non-canon comic book sequel to this episode about Stephanie)
The two drug dealers in MIA (killed by Sam to save Skaggs, the baby and its mother)
Any children of Lisa and No-Nose (their existence erased when Sam prevented their marriage)
Maggie Dawson in The Leap Home Part 2 (in the original history she did not go on the mission and did not die)
Lonnie in Black on White on Fire (We don't know what happened in the original history but it's possible he may have survived the riot)
Vince in A Hunting We Will Go (from memory, Sam killed him. Not 100% sure on this one)
Sam Beaterman in Shock Theatre (it's unlikely that Sam Beaterman would have been able to survive the unethical and inhumane experiments he would be likely to endure after Sam made them think he had multiple personality disorder)
Clifford in the Leap Back (killed by Sam)
The cop (killed by the assistant) and the assistant (killed by Sam) in Permanent Wave
The serial killer in Temptation Eyes (killed by Sam)
The man who was killed by the mummy in Ptah Hotep
Al, and later Chip, in A Leap For Lisa (but both were later saved after history was changed from Bingo's leap)
I'll do Season 5 later...