[Shoryutei Enraku] Seishin Kaihouron | The theory of releasing your real self (Nozoite wa Ikenai 7 - Do Not Peep! 7) [English] [Quick and easy translations]

[Theory of HEAVEN (CROW)] Onikuya Ken-chan (Anyamaru Tantei Kiruminzoo) [Digital]

(COMIC1☆6) [Crazy9 (Ichitaka)] Zessica no Koufukuron | Zessica's Theory of Happiness (Aquarion Evol) [English] [biribiri + Doujin-Moe.us]

Crow (Theory of Heaven) - Honey Kami the 2nd vol.0.7

(C78) [Kinokonomi (kino, konomi)] Kinokothical Theory (Various)

(C66) [SUBSONIC FACTOR (Ria Tajima)] The steady-state theory (Fullmetal Alchemist)

K's Theory

(C92) [Koniro Drops (Morishima Kon)] Rironjou 3-patsu made nara Taeraremasu. - In Theory You Can Tolerate up to Three Shots (Splatoon) [Chinese] [沒有漢化]

Futaba841 (Mitsuya Yoguru) - The Love and Pleasure Theory for Boys [ENG]

[Mira] Kodomo no Riron | A Kid’s Theory (School Girls Love Selection) [English] {Hennojin}

(C64) [Kokushi Tenshi (Various)] SPACE STRING THEORY (Uchuu no Stellvia)

[Kakashi Asahiro] Hakase no Renai Kaizouron | A Professors Theory on Love and Sex Reassignment Surgery (COMIC Situation Play Vol. 19) [English] [4dawgz + thetsuuyaku] [Digital]

(Knights Theory) [Snow Peach (Mipoko)] Naru no Anal kara Inspiration ga Waite Kuru zo (Ensemble Stars!)

[SHINSHIN] Shinshin Nijigenron | Mind and Body Two Dimension Theory

Kimi to no Shukumeiron - The theory of fate with you. | 與妳的宿命論

Orcs and juvenile ω love evolution theory

Kodomo no Riron | A Kid’s Theory

A Kid’s Theory

A Professors Theory on Love and Sex Reassignment Surgery

Innocence1 - Theory

Empty Theory 4 - Well Definitely Meet Again

Empty Theory 6 - Hearts Scheme

Empty Theory 2 - Sky High

Elements1 - Theory

Empty Theory 5 - Advantage

Empty Theory 3 - Cousin

Empty Theory 8 - Apparent Flash

Empty Theory 7 - Destroyed Family

Empty Theory 1 - After Pleasure

Soutaisei Virgin Theory

Soutaisei Virgin Theory

Rem no Koufuku H Ron | Rem's Happiness H Theory

Scapegoat Koufukuron | Scapegoat Theory of Happiness

Fuzzy Theory

[Kuroiwa Menou] Hitozuma Club Bijo to Yajuu-tachi (COMIC HOTMILK 2020-05) [English] {The Ancient Hentai Theory} [Digital]