I'll admit, I missed out on MLP when it had its moment in the spotlight. However, I am familiar with it due to my involvement with two of its fanworks. The first, and the one that also made me rediscover LBT, is Equestria at War, a total conversion modification for the WW2 grand strategy Hearts of Iron IV set in a magitech dieselpunk version of Gen 4's world, featuring complex narratives, politics, nation-building, and warfare:
https://steamcommunity.com/sharedfiles/filedetails/?id=1826643372It's quite a fun play if you have HoI IV and it inspired me to create my own dieselpunk world,
Paravian.
Another MLP story I've followed is an interactive fanfiction that crosses over with Cultist Simulator. The players vote on the actions of Velvet Covers, a noblemare who has been inducted into the occult world that hides behind Equestria's shiny exterior. She must brave the House of the Sun to find a way to save her world from annihilation:
https://forums.sufficientvelocity.com/threads/esquestria-the-house-of-the-sun-a-pony-cultist-experience.71721/MLP and cosmic horror is a strange combination, but it works quite well and I've taken some inspiration from it in The Lands Beyond, my upcoming Outer Wilds/LBT crossover quest also on Sufficient Velocity