The Source of all evil appeared multiple times in season 3 through 5 when Cole became the Source himself.

Belthazor is the powerful demon half of district attorney Cole Turner. Cole tries to suppress his demon half numerous times but he lost the trust of the sisters and was eventually vanquished in "Centennial Charmed" by Paige Matthews. Cole makes one more cameo appearance in season seven and ends up helping Piper.

The valuptuous Spider Demon (played by actress Jodi Lyn O'Keefe [She's All That (1999), Whatever It Takes (2000)] seduces older Chris and turns him evil. He then becomes a threat to Leo.

Tempest (played by actor David Carradine), the demon who controls time, appeared in the season one finale. He was mentioned once again in the season 3 finale "All Hell Breaks Loose" because he was the only one who could reset time to save Piper from what happened to her because of a crazy hippie chick. The catch was that Phoebe was to stay in the underworld.

Barbus is one of the weirdest demons ever to embrace the Charmed Universe. He happened to come up throughout the series at the most inopportune times. He has the ability to make someone's greatest fears become reality which essentially paralyzes them. He has affected each of the Charmed ones including Leo and Chris numerous times making it very difficult to actually vanquish him.