For my protoboards I have a bunch of the cheap chinese matrix boards, mainly because the're cheap and easy to obtain, and I have some older versions also with THT holes, but single sided and I think I prefer these slightly better.
I have long wondered about a protoboard with also a 2.54mm x2.54mm grid, but not plated, and for which the whole top side of the PCB is a GND plane, but with a small clearance distance from the holes, so you don't create shorts.
Besides that, The PCB's I design are also prototypes, and in anticipation to modifications I tend to fill unused areas with proto board like arrays. It's quite easy and quick to make some custom footprint in KiCad with a row of pads or a 2 dimensional array of pads, and such footprints can be fine tuned to the available area. KiCad also has "Footprint Wizards" written in Python. The Idea is to type in some parameters (such as pad size, pitch and number of pads) and then a footprint is created from it. I'm wondering if it would be handy if KiCad had a footprint generator explicitly designed for designing protoboard pad arrays, but in the end I think it won't be such a big difference from just drawing an array of pads.