Better Call Saul:

Eighty-Six Years. Kim after the series finale, to put it as unspoilery as possible, rebuilding (not least herself)...

The Sandman:

Poets and Dreamers: "how they met and became an item" backstory for Morpheus and Calliope.
***

The Guardian put out a list of Where To Start With Stephen King, which made me discover I have some firm King opinions, because I disagree with most of their choices. Given the sheer number of his books, this is bound to happen and doesn't mean their choices are bad, just that there are a lot of novels to choose from.

For example: My choice for the category "If you're in a rush", aka the one for readers who don't have the time or patience for a long Stephen King novel would be "The Girl Who Loved Tom Gordon". Only novella length, intense story, very sympathetic young heroine, executes its deceptively simple premise (young girl gets lost in the woods, manages to survive) beautifully.