A is for Attenuating his Axial Servo, which Data did in Generations to open a magnetically locked door.
B is for Troi's & Crusher's firm Insurrection Boobs.
C is for Causality Loop. The Enterprise-D was caught in at least one of them.
D is for Data's balls.
E is for Exocomps. Data was utterly fascinated with the things.
F is for Fat Ferengi.