Twilight x Tempest: Evening Star -After defeating the Storm King, Tempest found work by becoming leader of Twilight's royal guard. Tempest also learned friendship by Twilight, and it wasn't long before Tempest told Twilight she wanted more than friendship from her..but she wasn't the only pony vying for Twilight's affection. Due to them both being busy, Moondancer agreed to carry their foal.
Rainbow Dash x Princess Celestia: Scarlet Dawn -Being in the Wonderbolts gave Rainbow connections to the military, so when Celestia had to journey outside Equestia, she choose Dash to be her personal escort and guard. The element of loyalty rose to the challenge and stayed at Celestia's side. When a storm caused them to lose the group one night, they found shelter in a cave. Rainbow was herself around the princess, but still showed complete and utter loyalty. Celestia found herself smitten.