You won't find more a more complete list of examples, because the game assumes and uses your familiarity with our modern world. The categories are relative to each other, and you just need to pick one. Ask yourself: is it simple, moderate, complex, or advanced? These are very chunky categories that divide all of technology from doorknobs up to jet engines into a mere four categories, so it shouldn't be hard to estimate which a given proposed device falls into.
To demonstrate this process using your examples:
I'm going to assume that the rocket-propelled rollerblades are safe to use and therefore not just a pair of off-the-shelf rollerblades with some solid-fuel rocket engines strapped on. That means they've got throttle control and therefore liquid-fuel engines, a refuelling system, maybe a nozzle gimbal for directional control, and some wired or wireless means for the user to control them (on/off, throttle, angle and trim, etc.).
That's definitely not Simple (e.g. pulleys and weights), it's definitely not Advanced (e.g. jet engines), so it's either Moderate (e.g. an engine component) or Complex (e.g. a modern handgun). The example for complex includes automobile engines: this sounds like it has enough moving parts to have that kind of complexity, so say it's Complex and give it the appropriate DC of 25.
Then again, maybe they are just strapping some solid rockets onto rollerblades and naïvely thinking that this is a good, survivable idea. The engineering involved then is just figuring out how to strap them together and how to light them off, which is no more complex than operating shoelaces and a cigarette lighter, and therefore qualifies as Simple (DC 15). (The challenge of surviving their use is probably much higher, though.)
A gas-torch "lightsabre" is just a civilian flamethrower aka a big blowtorch. To make a safe one (there's that assumption again), requires quite a bit of precision gas-flow and materials engineering actually, but it's simpler than a jet engine (Advanced), so call it Complex with a DC of 25.
Of course, it would be easier for them to just buy one and paint an Old Republic or Imperial logo on it, so why they'd bother is unclear.
Note that these details I'm describing aren't actually your job to figure out: that's on them to figure out and describe to you. (This may require them to do real research if they want to create something that they can't describe off the top of their heads.)