D&D One Shot

The characters are good wizards who must create a safe place for a blessed chest. A character is celebrating a special anniversary.
It is at a sacred cave complex which is part of an ongoing struggle between powerful monsters.
There are a group of celebrating raiders searching for a person. And a friendly giant wants to protect a cursed mace.
At some point someone tries to steal from them.
As the adventure progresses people start breaking into song

The PCs are mutant criminals who must investigate the history of a crystal statue. Two of the characters have fallen in love. The mood might be... tense
There is a shapechanging assassin who comes with them.
The characters start with an attempted theft. Partway through they encounter a sand storm. If things are going nowhere a character has to make a Perception check.
It finishes with a religious ritual. Possible sequel... a character's homeland is under threat

The PCs are mutant charlatans who must collect a bounty on a mutant lizardfolk shaman. It might involve orcs.
There is a desperate druid who comes with them. they are part of same faction as a character.
The characters start with an explosion. Partway through there is a big fight scene. If things are going nowhere a deity sends a sign.
It finishes with the characters starting a journey.

The PCs are chaotic hermits who must defend a walled stone circle. Two of the characters have fallen in love. It might involve a criminal organization.
There is a well-dressed fey who works against them. they are the distant relation of a character.
The characters start at the scene of a murder. At some point they encounter a riddle. If things slow down it starts to rain.
It finishes with a reward of a favor. Possible sequel... a character's homeland is under threat

The PCs are successful monster hunters who must destroy a possessed wagon. The mood might be... relaxed
There is a popular sage who turns out to be the villain. they are the close relations of a character.
The characters start in a chase scene. At some point they encounter an unexpected admirer. If things slow down a character has to make a roll to notice something.
It finishes with a reward of a big favor.