Just watch all the Star Wars movies
15 hours I would suggest watching all time classics like Sopranos, Mad Men, The Wire, Breaking Bad, LOST or the Americans but since it is 15 hours I’d suggest watching The Night Of, Quarry, Luck (Dustin Hoffman hbo Series). Or just download one of David Lynch, Gaspar Noe, Christopher Nolan, David Villeneuve or David Fincher movies. Quality 15 hours are just guaranteed.
Best of the best:
Game of Thrones
The End of the Fucking World
Lost in Space is great imo. Music by John Williams as well, fucking great,
Just go on imdb top rated shows