At Mudbriar's funeral, Starlight Glimmer struggles to be a friend; she and Maud reflect on roads not taken. (Igneous and Pinkie provide flavour, rock and candy-based respectively). Also, there is the mirror lake....
Era: Post-Season 9. (See an index of my stories, sorted by My Little Pony Season).
Note: This site suggests "Mud Briar", but "Mudbriar" is what the fandom wiki uses and, for purposes of this tale, it sounds more poetic.
Image: Source is clickable on the image. The Image ONLY is by Delapouite under CC BY 3.0.