I realize that this may be better suited for a social science subreddit, but I believe there are a significant number of historians who specialize in the history of crime.
Many horror films end with a killer being ultimately subdued and killed by somebody they were attempting to murder, but has this happened in real life? Are there cases of established killers dying at the hand of a potential victim? As far as I know, no high-profile killers have been active since 1995, so this question does not violate the 20-year-rule.
I would define a serial killer as any person who seeks to kill multiple people, in multiple instances or killing. I would include economically-driven robbers who kill, like the Harp brothers.
Not killed, but serial killer Richard Ramirez, who terrorized Southern California in the early 1980's as "The Night Stalker", after a failed attempt at a carjacking, was ultimately overpowered by a vengeful public and beaten within an inch of his life before he was taken into police custody.
British serial killer Colin Pitchfork was also engaged in a violent struggle with a prospective victim, who he picked up as a hitchhiker. Rather than submit to his assault or trying to reason with him, this young woman reacted by fighting tooth and nail, causing him to almost crash the car; when he stopped the car, she jumped out and escaped. The woman is unnamed for privacy reasons in author Joseph Wambaugh's "The Blooding" non-fiction work on the first use of forensic DNA analysis to identify a criminal.
In both cases, it's illustrated that these particular killers expected to establish and maintain total control over their victims, who typically reacted as many of us might, by trying to reason and placate the killer; with a victim who reacted with a hysterical violence and put up a crazy amount of fight, the killers realized they could not maintain control of this particular victim and they risked injury themselves that could lead to identification; it's also implied that the sense of dominance and control is part of the gratification the killer receives in the act; take that away, and their motivation is diminished.
As a side note, you could also try your luck there /r/serialkillers/ . Some people on this sub are very knowledgeable about the history of serial killing.
I can't think about any of them killed by their would be victims but like /u/hatheaded said, there are some of them who were beaten by potential victims.