For the Tanfoglio Domina we carry one part, and it changes the gun considerably: a Toni System side mount for a red dot.
How a side mount works
Instead of sitting on the slide, the optic is carried by a bracket bolted to the side of the frame, using holes Tanfoglio drills at the factory on frames made for it. Because the frame does not move when the gun fires, the dot stays put while the slide cycles. That keeps the optic away from the slide's shock and keeps the slide light.
Which optic
The mount takes optics with the Trijicon RMR footprint. Many makers build to that pattern, so you have a wide choice of dots; check the footprint in your optic's specification.
Before ordering
The side mount needs the factory pre-drilled holes. Look at the side of your Domina's frame, or check its documentation. If the holes are missing, this mount will not fit.