danball senki
"Danball Senki (ダンボール戦機) lit. "Cardboard Chronicles" is a 2011 Japanese anime television series produced by Level-5 under the direction of Naohito Takahashi. Based on a plastic-model-building role-playing game, Danball Senki was broadcast in Japan on the TV Tokyo Network starting March 2, 2011." (from Wikipedia).
In 2021, the series received a mecha musume-focused spin-off in Soukou Musume Senki.