Homefront, a show from the 90s on ABC. It took place in the 40s.
American Dreams, which was from Dick Clark Productions, it ran in the 00s on NBC. It was about the 60s.
Ghost Whisperer, abruptly canned off CBS right after actor and radio host Jay Mohr left the cast in 2010.
The Greatest American Hero, lasted too short and so it is never re-runed much anymore. Wish it had lasted longer. Ran from 1981 to 1983, I think.
The Crazy Ones, was rather good then CBS claimed ratings fell off and Aaron Sorkin wanted more money to produce shows so it was destined to get canned in May. Then Robin Williams committed suicide.
Star Man. Was based on the movie. It was canned after one season in 1986-87.
Quantum Leap was abruptly ended without a clear ending. At one point there was to be a spin-off but nothing materialized.
Samantha Who was going somewhere and got canned abruptly. Christina Applegate had amnesia and was trying to figure out her past.
Client List, the other Jennifer Love Hewitt show was beginning to catch steam when it was canned in the middle of a storyline.
Body Of Proof, canned as it was also gaining steam. The scheduling of the show was mishandled from day one. It had decent ratings.
The Adventures of Brisco County Jr. and The Flash, two shows Fox tried in the 90s that were canned too quickly and that I still recall to this day.
Just some of the top of my head.
I think flash will be back soon