This is an interesting one that potentially opens the question what is a one-shot? Grim Tokens already posted the daily article and looks into the definition of a one-shot. My reply is going to consider the games that fit within a few criteria.
First, I’m considering only those games that are explicitly not about a one-shot experience. So Ten Candles, Dread, Grant’s one-page games … all gone. Please play those games, or even more like The King is Dead, Alice is Missing, Palanquin, Fiasco … really please play those games. But for me, today, not it.
Then from a gaming and rules perspectives, a fairly full experience. Sure, cutting stuff out that happens in campaign play is OK, maybe dropping some rules for a better game flow, but no major interventions. You should go out feeling like you played a proper session of game X.
Finally length needs to be bound to a single gaming session. No drawn-out games over two or three sessions. In and out.
We have a local face to face group whose mission statement is to organise one-shots. A lot of games ran are played for the first time, and will mostly last a session. Running games there gives you a good insight for this very question.
Ironsworn & Ironsworn: Starforged
The core mechanics of Ironsworn are a breeze to explain, and they have enough crunch. The killer tech is the pacing mechanism not only of an individual encounter, but the moves that essentially allow the players to stop their travelling, and even the adventure itself. And that is what supports one-shots very well.
I’m getting bored by how much I keep mentioning this game, but it is easily one of my favorite games out there.
Delta Green
On the other side of the equation is Delta Green. The genre and the setting give you a great setup to sit down, play, go home and never see each other again. Then there are a lot, and I do mean a lot, of published adventures to get you into it. Add the two together and you have an outstanding support for a one-shot.
The main issue with Delta Green is that the downtime between the missions is so well done it is a shame to miss it. And even if you play it out, it sings in long term play when it keeps grinding your character down with impossible choices.
Atomic Robo
Atomic Robo is a Fate game based on a very good comic book. Like Ironsworn it has rules that mimic the way plots are resolved in the source comics. The PCs for a hypothesis and roll to see if they are correct. You can see a similar approach in The Brindlewood Bay. Is allows for pacing of the session like no other game.
Bubblegumshoe
The simplest of the Gumshoe games I have read is Bubblegumshoe. Both the desired settings (teen sleuths) and the simplification of rules lead to a great one-shot game.