Source: https://www.pixiv.net/en/users/16186617

The artist's compilation of images from his Twitter and Fanbox accounts, as posted in his pixiv account.
Most are miscellaneous images featuring Shizuku or Astrea, though some appear to be short stories (though likely unrelated or non-canonical to the main story).

001-050: https://www.pixiv.net/en/artworks/63680717
051-088: https://www.pixiv.net/en/artworks/65556849
089-136: https://www.pixiv.net/en/artworks/66071664
137-178: https://www.pixiv.net/en/artworks/68727603
179-230: https://www.pixiv.net/en/artworks/71106657
231-298: https://www.pixiv.net/en/artworks/72458641
299-389: https://www.pixiv.net/en/artworks/74032584
390-439 https://www.pixiv.net/en/artworks/76424239
440-465: https://www.pixiv.net/en/artworks/77082175
466-567: https://www.pixiv.net/en/artworks/82467357