“We all know Rachel Lillis from the many wonderful roles she has played,” Taylor wrote on social media on Monday.
“She filled Saturday mornings and before/after school hours with her beautiful voice, great comedic timing, and amazing acting skills.”
She said Lillis was grateful for the support she received during her battle with cancer.
“It has made a really positive difference,” Ms Taylor said.
Her sister also confirmed Lillis’ death on a GoFundMe site set up earlier this year to raise money for her cancer treatment and move into hospice care.
“This was unexpected and we are deeply saddened,” Lori Orr wrote, adding that her sister’s health began to deteriorate last week.
“My heart breaks for the loss of my dear little sister, although I take comfort in knowing she is free,” she said.
The page has raised more than $100,000 (£78,000) – including donations from fans since her death was announced, who said she had “gone too soon and too young” and that her “light shone” through her work.
The money will now go toward remaining medical bills, a memorial service and “cancer efforts,” Ms. Orr said.
Lillis was born in Niagara Falls, New York, in 1978 and trained in opera at university before becoming a voice actress.
Her voice appeared in 423 episodes of the Pokémon series between 1997 and 2015, according to IMDB.
She has also voiced the Pokémon character Jigglypuff, including in the 2019 film Detective Pikachu and in the Super Smash Bros. video game series.
“Lifelong beer expert. General travel enthusiast. Social media buff. Zombie maven. Communicator.”