The official site for Gargantia has been updated with a preview for the goodies set to be released with the third Blu-ray box. In addition to offering a look at Hanaharu Naruko's full color manga, it previewed OVA original sisters Aleria, Onderia, Kuraria and Linaria, voiced by Minori Chihara (singer of the series' opening, voice of Haruhi's Yuki).
Chihara's Aleria, who crosses path with Kugel
The Hanaharu Naruko manga
There's also new tribute art from