Two Episodes of The Outer Limits Remake: Stitch In Time and Tribunal
Stitch in Time, with Amanda Plummer and Michelle Forbes, where a woman travels time killing serial killers and things take a different turn when her initial attacker is stopped, and Tribunal, where a Nazi war criminal is pursued, both essentially cover what I'm seeing here in Timeless.
The show Primeval also touched on time alterations rather well. I see this is lifted from a Spanish show, but it really isn't bringing anything new to the table anyway.