Astromech droids with piloting skills in the cockpit prevents travel aborting if the pilot boards an internally docked entity. (Link
Droids can be used in ground combat much like NPCs (Link
) and can also be disabled and captured. (Link
Medical droids can be used to assist in cybernetic operations. (Link
LIN droids are used to assist in mining. (Link
TT-8L Sentry droids report the movements of PCs, NPCs and droids through the room they are deployed in to their manager. (Read the description
I may have missed some.