The network announced in February the "Buffy the Vampire Slayer" spin-off from creator Joss Whedon would not be back for a sixth season.
"Buffy" ended last spring after seven seasons.
News of "Angel"'s cancellation inspired devout fans to stage two protests outside the WB's headquarters, the New York Daily News reported Monday.
Fans have also raised more than $35,000 to buy ads in trade magazines and to have a truck with a "Save Angel" billboard on its sides driven around Los Angeles.
They have also written letters to advertisers and network executives, the News said.
"We believe what the consumer wants should at least be listened to," Theresa Fortier wrote in a message on the SavingAngel.org Web site. "We've had Joss Whedon-created programs on for eight years, and this is the last tie we have to his universe."
However, WB executives insist the show will not be resurrected, noting its low ratings don't justify the high costs of making the special effects-laden series.