I’ve recently seen some bubble levels that attach to power tools, or are built-in. In theory, they’re a good idea, if you can see the level itself. I don’t know where you’re doing work, but I’m often in awkward positions where it’s not possible.
Over the past few years, I’ve also seen a lot of tools sporting lasers, which are intended to show the user where the cut line or drill point is.
Today’s invention is a combination of those two items along with a digital protractor.
A small circuit monitors 2 level sensors and turns on the laser only when the tool is level. You can then hold the tool in the proper position without taking your eye off the cut/drill point. Two dials, aligned with the leveling planes, allow you to set the angle (yaw and/or pitch) at which the laser turns on. This would allow you to drill angled holes with great ease. A casual perusal of the web doesn’t turn up anything that seems similar.
I would make it in two versions, one for OEM installation in a tool’s case/chassis, and a portable one that would be purchased with mounting adapters for all common manufacturers, or with a generic unit adjusted by the end user.