In the Harry Potter books, a Portkey is an object that can transport a person to another location.
The Portkey can be any old object, and is set up in advance to activate at a set time or upon being touched. When it activates, the portkey and anyone touching it are teleported to the location chosen when it was set up. They can be any old object, like an old boot, and in Harry Potter they're usually a piece of junk nobody would touch so that nobody accidentally gets Portkeyed anywhere. (So an old boot is often exactly what it is.)
Note that Portkeys are use-once (until they get set up again) and move with you.
What existing magic spells or magic items can be used as an equivalent or substitute?