So far:
Louis Koo, Raymond Lam (evil!!!) - A Step in the Past
Adam Cheng - The Greed of Man??? (He made me hate him lol)
Bobby Au, Jessica Hsuan, Marianne Chan - Witness to a Prosecution
Bowie Lam, Flora Chan - Untraceable Evidence
Nick Cheung, Maggie Cheung - Ups and Downs in the Sea of Love
Dayo Wong, Ada Choi - To uncatch the uncatchable
Bobby Au (his evilness at the beginning), Julian Cheung, Kenix Kwok - Take my word for it
Tavia Yeung - Vigilante Force
Raymond Lam - Survivor's Law
Andy Lau, Tony Leung - Duke of Mt Deer
Myolie Wu - Golden Faith
Big list I know, generally they are characters in my favourite shows hehe might add some later...
Just wanna add:
Bosco Wong, John Chiang - Wong Fei Hung
Sheren Tang, Charmaine Sheh, Maggie Cheung, Gigi Lai - War and Beauty