Every PB can only be used once. The exception of this is if the same actor/actress playes in multiple roles. ;-) Of course Faith and Tru Davies for example would both have Eliza Dushku as PB.

Alona Tal - Jo Harvelle
Amanda Tapping - Helen Magnus
Billie Piper - Rose Tyler
Cillian Murphy - Dr. Jonathan Crane/Scarecrow
Connor Trinneer - Michael
David Boreanaz - Angel
David Hewlett - Rodney McKay
David Tennant - The Doctor
Eliza Dushku - Faith Lehane
Eve Myles - Gwen Cooper
Freema Agyeman - Martha Jones
Gary Oldman - Sirius Black
Hugh Jackman - Wolverine
Jared Padalecki - Sam Winchester
Jason Isaacs - Lucius Malfoy
Jason Momoa - Ronon Dex
Jensen Ackles - Dean Winchester
Jewel Staite - Jennifer Keller
Jim Sturgess - Lelaund Gaunt
Joe Flanigan - Lt. Colonel John Sheppard
John Barrowman - Captain Jack Harkness
Kate Mara - Kate Kane/Batwoman
Katee Sackhoff - Kara Thrace
Katherine Heigl - Isabel Evans
Kyle Schmid - Henry Fitzroy
Luke Goss - Prince Nuada
Michelle Pfeiffer - Lamia, the Witch Queen
Nigel Bennett - Visser One
Paul McGillion - Carson Beckett
Rachel Luttrell - Teyla Emmagan
Ryan Robbins - Henry Foss
Sarah Knappik - Rachel Berenson
Sarah Michelle Gellar - Buffy Summers
Sarah Polley - Tabitha Smith
Steven Strait - Jacob Black
Yvonne Strahovski - Sarah Walker