Azeroth Survivor
Singular search, same game.
▶ Play Azeroth Survivors online — official entry
Free. No account. No WoW subscription. This site does not host the game and does not embed game files. The button opens developer Aethus's official browser version in a new tab.
If you see “Too many people are playing”, the official browser version is throttled on its small free server. Try off-peak hours or the Windows download — do not trust third-party mirrors.
“Azeroth survivor” (singular) and “azeroth survivors” (plural) are the same game in search. Google shows both because players type both. There is no single-player-only version called Azeroth Survivor and a separate multiplayer version called Azeroth Survivors — the same build has solo and up-to-5 co-op.
For a first run, the singular/plural question does not matter. The choice that matters is class: Warrior, Paladin and Hunter forgive the most mistakes. Use the class finder on the home page if you are unsure.
Verified-only policy: Elwynn timers and class numbers are stated as verified; later-zone numbers are not invented here. See the home page for the full verified / unverified list.