The optional secondary themes are:
馃珎 Friends Reunited
馃敽 Symmetry
馃 Crustacean
馃摷 Found Footage
馃暫 Groove
馃捑 Obsolete
馃 Nest
馃寪 Your Nation
Remember you can use as many or as little as you like, the only thing your game must contain are kaiju. They are optional so don't feel like you need to incorporate any of them if you don't like them. Thanks!