The DVDs, the BDs, the Drama CDs and the OST came with booklets that showed some of the character designs used for the show.
Booklets[]
Cover of the first BD
Back cover of the first BD
Cover of the booklet
Some promotional art
Character designs for Kanata Sorami and Rio Kazumiya
Character designs for Kureha Suminoya and Noël Kannagi
Character designs for Filicia Heideman and Shuko.
Some other stuff
Promotional art
Cover of the second BD
Back cover