D&D One Shot

The PCs are respected leaders of a cult who must defend a floating sea cave. The mood might be... manic
There is an insane noble who comes with them.
The characters start with an escaped monster. Early on they find a useful artifact. If things get stuck it starts to rain.
It finishes with a reward of deeds to a village. Possible sequel... a clue from a reward or treasure points to an infamous dungeon...

The PCs are outcast criminals who must win a sporting event. A character is celebrating a birthday. It might involve gnomes.
There is a shapechanging ranger who works against them.
The characters start in a chase scene. At some point they meet a rival group. If things slow down a deity sends a sign.
At the end there is someone imprisoned. Possible sequel... a character's homeland is under threat

The characters are good satyrs who must put on a fashion show. A character is being hunted by a a wise aristocrat.
It is at a sunken circus which has a programmed illusion involving a dancing seagull.
There are a group of orcs performing a ceremony. And a talented witch seeks to defeat a repulsive veteran.
At some point they notice an obvious clue.
As the adventure progresses people start to gather for a funeral

The PCs are infamous dragonborn who must create a holy coffin. Two of the characters have a bet about the evening. It might involve winter.
There is a drunk priest who comes with them.
The characters start in a fight. At some point there is a romantic complication. If things get stuck they discover a magic item.
It finishes with a reward of a pocket dimension.

The PCs are scarred sages who must complete a ritual in a magical ruins in the Shadowfell. It might involve the Feywild.
There is an eccentric necromancer who wants to do the same thing. they are the rival of a character.
The characters start at a burning tavern. At some point they encounter a thieving NPC. If things get stuck an old friend appears.
It finishes with a reward of a few magic items.