Peripheral LAUREN BACALL voiced the "Witch of the Waste" in the American version of HOWL'S MOVING CASTLE, alongside--
Primary CHRISTIAN BALE of BATMAN BEGINS fame.
Primary MORENA BACCARIN acted in DEADPOOL and its forthcoming sequel, the teleseries FIREFLY and its movie-sequel SERENITY, STARGATE SG-1, the 2009 version of V, and GOTHAM, as well as voicing characters for JUSTICE LEAGUE UNLIMITED and BATMAN THE BRAVE AND THE BOLD.
Primary BARBARA BACH amasses two whole credits in THE SPY WHO LOVED ME and the Italian "Star Wars" swipe THE HUMANOID.
Primary CATHERINE BACH, aka "Daisy" of THE DUKES OF HAZZARD, has one relevant credit in DRIVING FORCE.
Primary STEVE BACIC has roles in ARROW and many other TV shows, and appears to be the first person to play the character of X-MEN's "Beast," though without hirsute makeup.
Primary JIM BACKUS (not shown), aka the voice of Mister Magoo, had one role on THE WILD WILD WEST. He also voiced a character on the original GHOST BUSTERS but I haven't seen that show.
Peripheral OLGA BACLANOVA (right) acted in THE MAN WHO LAUGHS (a major inspiration on BATMAN's "Joker") with--
Primary CONRAD VEIDT, whose sympathetic "Gwynplaine" from LAUGHS gave way to the deep-dyed villainy of "Jaffar" in 1940's THIEF OF BAGDAD.