Sci-fi fans are not a passive lot, by and large. When they like something, they want to write about it, they want more of it, and they want to see it their way - hence, the multitude of Star Trek fanzines in the 1960s and 1970s. Let's enjoy some of the best art from 'em!
Nobody knows just how 'zines were made, or how many still exist, but the Fanlore wiki is the best resource out there. This list is in rough chronological order, and I'm going to focus on 'zines produced while the original series was on the air, because they're the oldest and I like old things. I'm also going to stick to what's called "gen" material, non-sexual in nature. Slash is a whole 'nother article.
1. The Fandom Gets Started.
Vulcanalia #1, January 1967
No actual art involved, of course, but this is an imporant historical document, considered to be the very first Star Trek fanzine. Look at the date: January 1967. The show debuted in September 1966. Damn! The fans (women, by and large) acted fast in those days. Also, by this point the term "Vulcanian" was still being used on the show, before the producers realized it sounded clunky.
2. Spock and Emma.
Plak-Tow #6, April 1968
Much to William Shatner's chagrin, Spock was Star Trek's sex symbol, so it's not surprising that the fans paired him up with one of the other big sex symbols of the time: Diana Rigg, as Emma Peel from (Not-Marvel's) The Avengers. For you youngsters, Rigg is currently playing Olenna Tyrell on Game of Thrones, and she's just as awesome as she ever was.
3 - 4. Spock and Barnabas.
Plak-Tow #9, August 1968
Artist: Kathy Bushman (most likely)
Vampires were already gettin' sexy back then, hence Barnabas Collins from the original Dark Shadows stopping by. And on the back cover, he annoys Spock by turning in to a bat.
5. Spock and Emma, Again.
En Garde unknown issue, 1968-ish
Artist: Kathy Bushman (f'reals)
En Garde was primarily an Avengers fanzine, with the occasional Trek crossover. The final issue was devoted to The Prisoner, and if there was any Trek content in that one - Patrick McGoohan's Number Six in the captain's chair would just be the best - I hope it surfaces eventually.
6. Early ASCII Art!
The Monthly Trek #1, January 1968
Artist: Craig Highberger
The Monthly Trek appears to have only existed for a single month (irony in spaaaaaace!), but it was long enough for Craig Highberger to make this piece on his typewriter. Oh yeah, his freakin' typewriter. Think about that. I'll bet it wasn't even a fancy-pants IBM Selectric, either.
7. Oh, Harlan.
ST-Phile #1, January 1968
Artist: Bjo Trimble
Illustration from an article entitled "What We Did on Our Visit To Desilu," by the legendary Bjo Trimble. She was a bigger fan of Star Trek from the beginning than you'll ever be of anything, and the entire article is available in PDF form from Laura J. Sweeney's website, as are other neato tidbits from ST-Phile and Spockanalia. And if you don't know who Harlan Ellison is, go watch Dreams with Sharp Teeth. His book about the writing of "The City on the Edge of Forever" is also one of the most brutally honest takedowns of Trek worship (and especially Roddenberry worship) you'll ever read.
8. Oh, Chekov.
Stardate #1, June 1968
Artist: Jane A. Bowers
I'm not at all certain what's going on here, but whatever it is, I approve. Also, note the tribble cameo.