If you're looking for manga similar to Fullmetal Alchemist: Premium Collection, you might like these titles.
A twin brother and sister who're polar opposites, and their work with the military.
It has been nearly twenty years since the last Great War, and while smaller skirmishes are still taking place across the world, peace is mostly the norm. In the Fuso Empire, Sakamoto Mio is about to join the war effort against the Neuroi alien invaders. She will have to distinguish herself among the other hardworking cadets if she is to become a full-fledged Strike Witch. Soon, she will have the chance to prove herself in battle, as the Neuroi launch their latest brutal attack.
One day, the entirety of the Earth was suddenly reborn into a parallel universe, and everything outside of the planet became known as "the other space". In that parallel universe, there is a three-person group that operates a general store called the "This-and-That Shop", where they spendidly solve the requests and cases that people in trouble bring to them!
14 years have passed since the "White Hero's" and the "Black Demon King's" decisive conflict during the war of Black and White. The world, now lacking of a Hero, was domineered by self-proclaimed "Heroes" who were showing off their power. However, some mysterious twins turn the tables around with their wisdom and ability...!