You should have a look at https://1shotadventures.com/ ! They have a variety of free one-shot stand-alone adventures for all kinds of genres, with pregenerated characters for each. It's all 4th edition, but the conversion between versions shouldn't be bad (and like GoldSeal said, 4Ed Lite is free!)
GURPS
Oo haven't heard of him before, there's a ton here.
Any favorites or one you've tried that i should look at first?
I'm afraid I haven't actually run any- I mine them for ideas, but I've got a long term game I host, so I haven't had the chance yet!
The Star Trek one was how I found the site; Bombshell of Tomorrow is one of the few superhero one-shots I've found that has potential...
Cool, I'll peek at those first
I recommend using the 4th Ed lite version (free), and using the Caravan To Ein Arris (also free).
Thanks!
This one right? The adventure is on the same site. https://warehouse23.com/products/gurps-lite-fourth-edition
And that's neat, Caravan To Ein Arris is also in the back of the book I have, I didn't notice.
Right in the book, there's a starter solo adventure called "All In A Night's Work". For a whole table, I would recommend converting free oneshot 4e adventures like the other commenter.