… This sounds vaguely suggestive.

Thank you. I will.

no, the fanfics are not official and are not part of the show. they do their own work

Filthy Rich goes to the rock farm, on Pinkie’s recommendation, to buy a headstone for Spoiled. Who he…“didn’t” arrange a little…“accident” for. Anyway, he and Marble find each other charming and sexy so they date and get married and totally make out and stuff.
 
or
 
Pinkie convinced Marble to make and bring her special Mourning Marzipan for Spoiled Rich’s funeral. Not-Gordon Ramsay pony tastes some and likes it. Then, it turns into Cinderella, except instead of a prince trying to find who fits a shoe, it’s a screaming stallion ordering ponies to make him marzipan. He tastes Marble’s and declares he loves it and her. Marriage.
 
or
 
Her kindness and cuteness doesn’t just redeem the real Grogar, it shows him what love truly is. She comes to love him, as well. Also, Spoiled Rich is dead.
 
…or she just ends up with a Big Macintosh recolor, I dunno.

@ABronyAccount  
Going to read it, but with the switch of the medium it loses the Canon Treatment.

@Havock  
Season 10 is coming in dead tree form, though.

@Background Pony #C333  
You DO realize that the show is over, right?

I’m preety sure they could do something good with her officially

@dsagent  

We got married and died and went to Heaven
 
THE END

@Havock  
Marble Pie and Braeburn could write a book together imagining themselves as a cowboy / cowgirl outlaw couple.

@Background Pony #052D  
They became Equestria’s most notorious criminals!

While each working on their family farms, Marble Pie and Braeburn meet each other from afar across the river running thru Ghastly Gorge between the Rock Farm and Appleloosa. After some initial awkwardness, they eventually develop a unique friendship. A friendship that could turn into something more…

She murders Sugar Belle and assumes her identity, fooling Big Mac until after their first foal. The plan works, Big Mac is overjoyed at this development and they lived happily ever after and nopony went to jail!

They did her dirty.

@Cyborg_pony  
Limestone: “KEEP YOUR FAMILY AWAY FROM HOLDER`S BOLDER!”

She meets Troubleshoes, and they live happy lives with 3 kids in the countryside.

I kinda prefer something a little more concrete than just using your imagination.
 
Headcanons are fine and all, but nothing beats actual canon (though I guess that depends on what the canon thing is).

Que the ocs.

@Backgroundpony  
I accept it as canon.

Oh I have some ideas alright.

Marble died surrounded by everyone that ever loved her, her cats.