[Cthulhu_]

Ion drives ionize particles like xenon and expel them; they're much more fuel/weight efficient than burning fuel but they still use fuel, unfortunately.

There's been a number of pure electric propulsion proposals or prototypes, but they've all turned out to be a hoax; the latest one I recall was the EmDrive [0], where any paper claiming it produced positive thrust was debunked with the measurements having been influenced by outside forces.

The TL;DR is that reactionless drives are not possible due to Newton's third law. This page / this website is always a great resource for things like this, it's in the context of writing science fiction but it has tons of research: [1]

[0] https://en.wikipedia.org/wiki/EmDrive

[1] https://www.projectrho.com/public_html/rocket/reactionlessdr...