Various is the correct author for any book with multiple unknown authors, and is acceptable for books with multiple known authors, especially if not all are known or the list is very long (over 50).
If an editor is known, however, Various is not necessary. List the name of the editor as the primary author (with role "editor"). Contributing authors' names follow it.
Note: WorldCat is an excellent resource for finding author information and contents of anthologies.
Good example of the most distinctive literary trend of the day: web serial fiction / wiki fiction. Also of the shortcomings of same: the committee fragmentariness and unmanageable hugeness. (I cut this short at page 1000. And this is only one of three giant ebooks of the whole wiki. Phew.)
That's the medium. Its genre is post-pulp post-Lovecraft urban fantasy-horror - the most popular genre? (Aside from old stalwarts, trash romance and MFA lit.) And style's the uncommon pseudoacademic register of Lovecraft's original pulp.
Its achievement is to dispense with characterisation and rely entirely on atmosphere and startling concepts. There's no protagonist and only hints of antagonists (besides the thousands of SCP objects themselves).
The Foundation is ludicrously powerful - they've global jurisdiction over law enforcement, run hundreds of fatal human experiments, retain a vast staff and holdings. In order for this to work as horror, they need equally elevated foes - and so they do: they're always being infiltrated, manipulated, stolen from, exsanguinated or bombed. The Foundation commits many atrocities (contrast Delta Green, Dresden Files, Agents of Shield, the X-Files, which are much more anti-authority).
It has all the ordinary kinds of horror - monsters, disease, body horror, mind-rape, invisible forces, alien geometries - but also the greater, rare horror of exponentiation, of facing a foe with the potential to suddenly explode beyond all containment and never stop growing. Another distinctive bit is its metahorror: objects which know the rules of the story and about other objects.
I recommend reading this with the images disabled. They're a labour of love, I know, but the imagination is easier to scare than the eye. Good queasy fun.
A serial collection of crowd-sourced strangeness, the first volume alone is massive. Each SCP is written as a memo summarizing how each strange object/individual is locked away for the safety of mankind and what has gone wrong. I've made it to SCP-104. Quality is highly variable from forgettable to nightmare inducing.
My standouts: SCP-87 (The Stairwell), 82 (Fernand), 73 (Cain), 96 (Shy Guy), 27 (Vermin God), 18 (Super Ball), 36 (The Reincarnation Pilgrimage of the Yazidi), 49 (Plague Doctor), 52 (Time Traveling Train), 81 (Spontaneous Combustion Virus), 93 (Red Sea Object)