D&D One Shot

An outline for a one-shot adventure with the situation, what the characters are, the aim of the one-shot, events during it and an ending.

The PCs are all shapechangers who must survive a long coach chase. The mood might be... relaxed
There is a talkative paladin who tries to help them.
The characters start with a fireball. Early on they encounter a magical door. If things slow down a prisoner escapes.
Afterwards there is a reward of the key to a planar portal.

The PCs are an elite military squadron who must find a beautiful casket. It might involve water.
There is a hilarious barbarian who betrays them partway through.
The characters start with the loan or gift of a powerful magic item. Early on there is a significant change of pace. If things get stuck a villain turns up.
Afterwards there is the group all sharing a joke.

The PCs are hungry knights who must destroy an orcish boat. It might involve elemental air.
There is a vengeful alchemist who offers them aid. they are part of same organisation as a character.
The characters start during a heist. At some point foes try to ambush them. If things are going nowhere a character has to make a saving throw or Perception check.
Afterwards there is a funeral. Possible sequel... a foe returns more dangerous than before

The PCs are brave farmers who must protect an elven ring. It might involve elemental water.
There is a popular local who betrays them partway through. they are the childhood friend of a character.
The characters start with an escaped beast. Partway through an ally turns out to be an enemy. If things get stuck they find a written note.
At the end there is a reward of a few potions. Possible sequel... the adventure becomes the first of a multi-part quest around the same theme

The PCs are all undead who must recover a sacrificial spear. The mood might be... relaxed
There is a treacherous priest who comes with them. they are the rival of a character.
The characters start running away from something. Partway through they meet an old foe. If things get stuck there is a murder.
It finishes with a reward of an expensive meal.