Fusion doesn’t get many mentions in the big two science fiction franchises, perhaps because it’s not considered sufficiently advanced. Star Trek spacecraft generally use matter-antimatter annihilation for their warp drives (except for Romulan vessels, which use artificial singularities), and Star Wars spacecraft use “reactors”, which might possibly be fusion reactors, but are usually considered to be “hypermatter reactors” in the Extended Universe literature.

The most prominent mention of controlled fusion as a power source in the Star Trek franchise is in several Deep Space 9 episodes, where it is mentioned that the Cardassian-built space station is powered by laser-induced fusion reactors. It is generally understood that the impulse drive on a Starfleet vessel is powered by fusion reactors of some sort. All use deuterium fuel. Klingon ships use tritium in their warp cores, so it’s possible they may use it in their impulse reactors as well. Apart from space stations and impulse drives, fusion has been known to power at least one individual house.

In Star Wars fusion is usually a small and mobile power source. A fusion furnace is mentioned in the Empire Strikes Back novelization, as Luke sets up his camp on Dagobah. Power droids are walking fusion reactors. On a larger scale, some of the smaller spacecraft may be powered by fusion reactors, and even those powered by hypermatter reactors may use fusion reactors for auxiliary purposes.

As for plasma, it gets plenty of mentions in Star Trek, as well as in Star Wars lore.

Plasma (or “electro-plasma”) is the life’s blood of Starfleet vessels, and seems to be the primary product of the reaction in the warp core. Its power generates the warp field in the warp nacelles. Starfleet vessels are full of plasma conduits, whose function is essentially the same as that of copper electric wires in our time. There are also various plasma weapons, most notably the Romulan plasma torpedo.

In Star Wars lore some blasters (such as those used by the clone troopers) fire plasma bolts. These are particularly effective against droids. Most notably of all, the lightsaber blade is composed of plasma.

The uses of boron in either franchise are left as an exercise for the reader.

Sources: Memory Alpha, Wookieepedia, Star Trek: Deep Space Nine Technical Manual, The Empire Strikes Back (novel)