As a DM, what is something you always put in your campaings? Like an item or a character with a certain trait?

As a DM, what is something you always put in your campaings? Like an item or a character with a certain trait?
For me its gunpowder and zeppelins (or some other kind of flying ship)

I have a love for putting various cloacked figures of ambiguous supernatural or alien origin that trade with the party.

Pic very related.

For me I tend to have a few things carry over:

> Ruins of a prior ancient and powerful civilization

This varies depending upon the setting and rules, but is meant to be a back up plan for if the players don't want to follow the main plot and instead go dungeon-delving and murder hobos.

> Classes/races outside of the official published material

For example, in D&D 5th edition I've got a campaign going where all of the stuff from the 4 main books (PHB, MM, DMG, SCAG) is allowed and can be found. But some things (usually classes or races from earlier editions of D&D, along with the UA races and archetypes) are "hidden options" for the players. If they come across these individuals throughout the adventure I then "unlock" that race or class to be playable should they die and roll up a new character.

> The BBEG is objectively evil, but has a reason for doing so

None of this Saturday Morning Cartoon villainry, my BBEGs have an actual reason for doing all the evil they perpetrate in my campaigns. Usually it's some form of, "I know better than the rest of the world, so bend to my whims," but there's evidence to support these claims.

this guy

a traveller from somewhere far off who wanders into town looking for skilled warriors to fight and is kind of an ass about it. He makes for some easy one-session antagonism and can be made into a recurring character if the players like him. I find myself using him and his entourage in quite a few games

I really liked that guy.

In a major city of every campaign I run there's always a pub populated by strange men in black leather armor.
The pub is always called "Ye Olde Blue Oyster"

I kek'd

Mine is similar: Tavern names are always sexual innuendo. Classier taverns are have more subtle innuendo for names, poor tavern names are downright ribald, but they're all double entendres.

Dwarf Monks. Of the classic kung-fu movie shaolin style, not the christian type

The Scholar/Sage/lore monkey that none of the players wanted to be is always sassy and sarcastic but has a heart of gold and is always reliable.