An anthology by various mangaka dealing with the theme of children. U12 Kodomo Fellows was given to readers who sent in an application that was included in volume 30 of Harta along with a seal included in all Harta volumes released from December 2015 to January 2016. The offer was later repeated with an application included in volume 34 of Harta.

Cover illustration: Michiko Shin
Table of contents illustration: Seira Fukuta

1. Kyou no Ryuuko-chan (今日の柳子ちゃん) [Michiko Shin]
2. Yama no Ko, Machi no Ko (やまのこ、まちのこ) [Tetsuya Nakamura]
3. Rojiura Muse (路地裏ミューズ) [Fumika Higa]
4. Kodomo (こども) [Ryouko Kui]
5. Jijii to Mago (じじいと孫) [Masao Ootake]
6. Daitouryou~! (大統領～!) [Suisei Matsumoto]
7. Ocha no Okeiko (お茶のおけいこ) [Kaoru Mori]
8. Kaeru no Ko wa (蛙の子は) [Minami Kimura]
9. Mimic no Miru Yume (ミミックの見る夢) [Kiyoto Shitara]
10. Midoriiro no Isu (緑色の椅子) [Takuto Kashiki]
11. Takashi-kun wa Hankouki (たかしくんは反抗期) [Yuki Matsumoto]
12. Shortcake Story (ショートケーキストーリー) [Satoshi Fukushima]
13. Noppo ga Iru (のっぽがいる) [Nami Sano]
14. Asa no Kourei Gyouji (朝の恒例行事) [Ichika Ootsuki]
15. Waga Ko e no Himitsu (我が子への秘密) [Ichika Ootsuki]
16. Watashi no Tomodachi wa Ii Ningyou (わたしの友達は良い人形) [Namiko Ogata]
17. Chichi wo Sagashite: Tarou to Tayura Hahaue-sama e Bangai-hen (父を探して多朗と多由良母上さまへ番外編) [Aki Irie]
18. Hyper Miracle☆Small Fashion GO GO (Hyper Miracle☆Small Fashion GO GO) [Sakura Sawa]
19. Kemuri to Mitsu (煙と蜜) [Hiroko Nagakura]
20. Tenshi no Youna Mono (天使のようなもの) [Yaya Takaesu]
21. Chiaki Blossom (ちあきブロッサム) [Ebisujima Sato]
22. Kodakara (子宝) [Daichi Kawada]
23. Chester no Bouken (チェスターの冒険) [Kiyoshi Katou]
24. Kemuri Makimaki Jidai (煙巻き巻き時代) [Yoh Unoshima]
25. Eien no Alice (永遠のアリス) [Sawako Arashida]
26. Danchi Neko (団地猫) [Tetsuo Utsugi]
27. Nee-chan Makoto Kamaboko (ねーちゃん・まこと・かまぼこ) [Mariko Kikuchi]
28. Mugiwara Boushi no Onna no Ko (麦藁帽子の女の子) [Natsuko Takahashi]
29. Ice Cream (ICE CREAM) [Lun Lun Yamamoto]
30. Itoko no Onee-san (いとこのお姉さん) [Ahikito Tomi]
31. Masa to Reiko (マサとレイコ) [Taiga Sassa]
32. Hagane no Shounen, Tetsu no Okite: Lost Child (鋼の少年、鉄の掟【ロストチャイルド】) [Kouhei Nishi]
33. Kaisetsu wa Natsuno-san de Onegaishimasu (解説は夏野さんでお願いします) [Kanae Yamada]
34. Rui-chan no Henshin (るいちゃんの変身) [Hirona Takahashi]
35. Kaede-kun wa Nakanai (楓くんは泣かない) [Ayumi Hara]
36. Chiguhagu-tic Hug (ちぐはぐチックHug) [Inoue Kinu]
37. Henshin wa, Kabocha Pan (返信は、かぼちゃパン) [Kizuku Takada]
38. Kappa Youchien (河童幼稚園) [Kano Ninomiya]
39. Watashi ga Chicchai Toki no Hanashi (私がちっちゃいときの話) [Sakura Hamada]
40. Ijimerarekko ga Kuru! (いじめられっこが来る!) [Takashi Wada]
41. Seiko Oba-chan wa Amayakashitai (星子おばちゃんは甘やかしたい) [Chisato Hatada] (畑田知里)
42. Aya to Rena (あやとレナ) [Fumi Nakanishi]
43. Mukidou Mukashibanashi Sono 1: Ari no Kuni (無軌道むかしばなしその1 ありのくに) [Kaoru Maruyama]
44. Mukidou Mukashibanashi Sono 2: Sakata-kun (無軌道むかしばなしその2 サカタくん) [Kaoru Maruyama]