Got the bike 3 months ago and I have done following:
Akrapovic full titanium exhaust with the up map
Comp Werkes fender eliminator
Ducati performance tank protector
Ducati performance bar ends
CRG levers
Zero Gravity windshield
Of course I do not know what your taste is but I can only mention which accessoires I mounted. (and I thought were cool..)
Rear hugger in carbon (matte Moto Composites)
Seat cowl in carbon (matte Moto Composites)
Gold cutch/front brake levers (Rizoma)
Silver reservoirs rear and front brake / clutch (Rizoma)
Clear clutch cover (Ducabike)
Tail light with integrated turn signals (Competition Werkes)
Litium-ion battery (WPS)
Full titanium Akra (you got that!)
Racing air-filter (K&N)
Motorlift (BS Motoparts Germany)
Ducati Panigale protective Bike Cover (Ducati)
Throttle spacers (panigalespacers.com)
Electronic push-button power shifter (Pro Shift UK)
Last but not least; just something very nice which does not make your bike ride any better, faster or even look cooler.. The famous Pocher ⅛ scale 1299-S model.. Just great to have!