3/4" is 19.05mm. I couldn't find any rocker switches with exactly that hole size, but here are 11 choices that use 18mm and 18.2mm holes. All are secured with a back-side nut, so the difference in hole size shouldn't be critical. If you have a row of switches, just use a straight edge to line them up as you tighten each nut.

The E-Switch RR3130 Series look like a good match for what you have, but with slightly smaller wire lugs. They use a small alignment keyway that has a 1.1mm radius, so the fit should actually be really close. Click the little PDF document symbol just to the left of the photos to see the datasheet.