A few more that I've come across. Varying degrees of sexiness, some are so quick you might miss them but I'll take what I can get.
Michelle Williams, Me Without You, close up of her belly button being kissed, no tongue unfortunately.
The TV show Invasion, Alexis Dziena has sand poured in her belly button and in another ep her belly is kissed.
There's an episode of Heroes where Ali Larter seduces the flying guy, she's in his lap with her belly right in his face and he's kissing her belly button.
Mischa Barton, Octane, a guy pierces her belly button, ices it and then kisses it.
Kim Dickens in an episode of Out Of Order, get's her pierced belly button licked.
Charisma Carpenter, Flirting With Danger, stomach, belly button kissed. Not really focused on, but it happens.
Courtney Cox, The Runner, her stomach is kissed, belly button is licked if you watch closely before she's sitting up to kiss the guy.
Tia Carrere, My Teacher's Wife, belly button licked, quick but there.
Dogtooth, it's a messed up movie, but there's a scene where the middle sister is asking the older sister where she'd liked to be licked, scene ends with her pointing to her belly button and getting it licked. Actresses are not related.
Liv Tyler in Stealing Beauty, in the sex scene at the end her belly button is being kissed at one point.
Sarah Wayne Callies in an episode of Walking Dead gets her belly licked.
Sheree J Wilson, Dallas, there's a scene where she's putting on sun tan lotion and fingers her belly button, it's pretty sexy.