Beorn from The Hobbit is assumedly a vegetarian, at least in his human form.
"Despite being incredibly powerful, Beorn respects all life forms, with the absolute exception of Goblins and Wargs" (http://lotr.wikia.com/wiki/Beorn).
Spock the Vulcan science officer and first officer on Kirk’s
Enterprise from the original Star Trek series is a vegetarian.
"In the episode“All Our Yesterdays”, Spock and McCoy find themselves trapped in a prehistoric ice age of the planet Sarpeidon. A cave-dweller named Zarabeth offers them shelter when they nearly freeze to death in the harsh climate. Later, Zarabeth offers Spock some food. Spock asks Zarabeth if it is animal flesh; she reports that there isn’t much else to eat. Spock makes a plan to build a greenhouse, then decides to eat the meat in the meantime. Soon after, he chastizes himself, calling his behavior disgraceful, establishing Spock’s vegetarianism for the first time on screen."
Also from Star Trek series Vulcan science officer T’Pol is a vegetarian or vegan.
"In the third season episode “Carpenter Street”, T’Pol and Archer find themselves in an early 21st century fast food drive-through. After Archer orders a hamburger for himself, T’Pol, who has been studying the menu, asks, “Does the fiesta salad contain animal products?” The woman taking the order says, over the intercom, that it does not, but offers to upgrade the salad with bacon for just 75 cents. T’Pol apparently loses her appetite at this suggestion, and decides not to order anything."
(http://www.redhotvegans.com/2012/10/where-no-vegan-has-gone-before/).
In Star Trek: The Next Generation almost everyone is apparently vegan.