D&D One Shot

The PCs are insane tabaxi who must run a tavern for one night as a favour for the owner. It is frequented by adventurers. One or more characters has an inquisitive mount. It might involve bullywugs.
There is an angry bard who comes with them.
The characters start camped and about to be attacked. At some point there is a chase scene. If things get stuck a planar portal opens.
Afterwards there is a reward of deeds to a city. Possible sequel... an ally becomes the main foe or threat

The PCs are famous leaders of a religion or temple who must make a trade with a mutant tree-monster. The mood might be... creepy
There is a well-dressed druid who hates one of the characters. they are the close relations of a character.
The characters start at a burning tavern. At some point they meet a friend of a character. If things are going nowhere a ghost gives them aid.
Afterwards there is a newborn or child on the way.

The PCs are feared leaders of a religion or temple who must empty out an elemental graveyard. The mood might be... deadly serious
There is a hilarious monk who works against them.
The characters start during an attempted escape. At some point they encounter a sand storm. If things are going nowhere a character has to make a saving throw.
At the end there is a reward of deeds to a city. Possible sequel... an evil organisation's plans were ruined and try to take revenge on the characters

The PCs are cursed rogues who must solve why they are stuck in a dream. It might involve rebels.
There is a desperate ruler who betrays them partway through.
The characters start on the road about to encounter someone. Early on they encounter an unexpected admirer. If things slow down a deity sends a sign.
Afterwards there is a reward of lots of platinum.

The PCs are emotional urchins who must find a murderer at a masked ball. It might involve devils.
There is a religious adventurer who tries to help them.
The characters start at a disrupted funeral. Early on they encounter a tornado. If things get stuck one of their allies tries to leave.
It finishes with the characters starting a journey.