Asura Cryin', Suisei no Gargantia Recommendations
Although the genres are different, the similarity is that they used mecha as their fighting combatant. Though the unique aspect of using the mecha, is mostly friendship, which means they understand several conflicts in their view and that they want to trust each other to take down their opponents.
Gargantia follows a soldier with an AI mecha where they are caught up in the war but escapes in a strange planet. The AI mech has some "human characteristics" and consider a friend to the main character. Asura Cryin follows a high school boy, who's childhood friend is a ghost and worked together to take