It started as a joke among the members of our Ask blog that all the Pie sisters prefer tall and slim stallions, but now I feel like these couples just make sense. Trenderhoof is the one who likes independent, harsh, hard-working rural ponies, and in contrast to Applejack, Limestone would adore his attention because she's always secretly craved a romantic relationship but is too tsundere to admit it. Zephyr, being Fluttershy's brother, knows how to handle shy and anxious ponies, and Marble would quickly fall in love with him and support him in every way she could. Even though the relationship between Marble and Zephyr might be problematic because both of them have some unresolved issues, it's much better for them to try and love each other than to pine over somepony who wouldn't love them back. I think I have some new fav ships