Parodies
- omega strikers 4
- omegane teacher 1
- omishi magical theater risky safety 7
- omniscient readers viewpoint 3
- omoide no marnie | when marnie was there 1
- omoikkiri kagaku adventure sou nanda 37
- omori 94
- once upon a forest 1
- once upon a time 6
- once upon a time... space 7
- one big happy 5
- one kagayaku kisetsu e 41
- one off 3
- one outs 2
- one piece 7595
- one punch man 1900
- one room 2
- one room hiatari futsuu tenshi-tsuki 1
- one week friends | isshuukan friends 32
- onechambara bikini samurai squad 1
- onegai anna sensei 2
- onegai asakura-san 1
- onegai my melody 212
- onegai ranking 5
- onegai teacher | please teacher 428
- onegai twins | please twins 152
- oneshot 40
- ongeki 206
- oni 2
- oni chichi 75
- onidere 10
- onigokko 4
- onihime vs 7
- onii-chan asa made zutto gyutte shite yoru made motto ecchi shite 2
- onii-chan dakedo ai sae areba kankeinai yo ne 30
- onii-chan wa oshimai 488
- oniichan no koto nanka zenzen suki janain dakara ne | i dont like my big brother at all 12
- oniisama e... | brother dear brother 1
- oniku daisuki zeushi-kun 1
- onimusha 34
- onirism 2
- only yesterday 4
- only you 1
- onmyoji 43
- onmyou taisenki 132
- onmyouji ayakashi no megami inran jubaku 1
- onore no shinzuru michi wo yuke 1
- onsen musume 1
- onward 12
- ookami kodomo no ame to yuki | the wolf children ame and yuki 18