My favorite action/fantasy manga that may include concepts of warfare, but didn't quite fit into the other list because they're more shounen-esque and focus more on the action than the tactics.
Manga with a strong focus on fighting, warfare, and/or strategy/PVP team tactics. Great balance of peppy shounen, fast-paced action, dark and gritty, adventure, strategy, intelligence, and growth. If you like one of these...
My favorite manga featuring "Isekai" or other other-world fantasy elements.
Manga where characters don't fall in love instantly and the romance is more subtle. Romance may or may not be the main genre, but it's really satisfying to see their interactions and relationships change over time.