Laser Weapons is a tech "tree" (it's linear) that will get us access to newer weaponry, all very good useful stuff. If we go down this tech tree we'll get Laser Rifles, which are one of the best weapons in the game.
We also eventually get Laser Cannons, which are actually Interceptor (airplane) weapons. They're okay as far as craft weapons go, but they can make you a lot of money if you sell them. We can't get them for a while though.

Motion Scanners let us see units that have moved that turn - useful for knowing enemy positions. They also aren't too bad for making money early on.

Medkits will let us heal soldiers and stuff. Personally, I don't see too much use in them, soldiers don't usually survive shots, and Medkits don't actually revive fallen soldiers. But maybe they're more useful than I think?