Just about every weapon can be purchased with some kind of interesting effect:
Lightsabers with pulsing energy Guns with glowing targeting sensors Bowcasters with laserpointers
It would be great to have some purchasable Shields, Focuses, and Generators that also have small but interesting effects.
For example,
Holding a cartel shield could produce an energy oval around/above the player's wrist. It could even match the color crystal, increasing the worth of color crystals to previously uncaring characters. A generator could produce sporadic lightning effects to dance up and down the arm. A focus could produce a soft glow or waves of energy.
Keeping these effects as exclusive to cartel items would allow those who don't want any effects to keep a normal offhand.
Thank you for your time.