Pogzilla wrote...
Suggesting a Gender Bender tag.
TSF Monogatari Append 1.0
https://www.fakku.net/doujinshi/tsf-monogatari-append-10
gender bender
Yousei-san ni Onegai!?
https://www.fakku.net/manga/yousei-san-ni-onegai-japanese
gender bender
Farfalla
https://www.fakku.net/manga/farfalla-english
gender bender
FARFALLA Due
https://www.fakku.net/manga/farfalla-due-english
gender bender
PIG
https://www.fakku.net/doujinshi/pig-english
gender bender
Kanojo no Sentaku - Senou Natsuru no Baai
https://www.fakku.net/doujinshi/kanojo-no-sentaku-senou-natsuru-no-baai-english
gender bender
I'm a Guy!
https://www.fakku.net/doujinshi/im-a-guy-english
gender bender
(Pretty much anything from the Kampfer series)
Trans Trap
https://www.fakku.net/doujinshi/trans-trap-english
gender bender
Lovery Summer Girls!
https://www.fakku.net/doujinshi/lovery-summer-girls-english
gender bender
Riko Scoop 2
https://www.fakku.net/doujinshi/riko-scoop-2-english
gender bender
Kyonko to Issho
https://www.fakku.net/doujinshi/kyonko-to-issho-english
gender bender
Manatsu no Yoru no Yume no Mata Yume no Mata Yume
https://www.fakku.net/doujinshi/manatsu-no-yoru-no-yume-no-mata-yume-no-mata-yume-english
gender bender
Manatsu no Yoru no Yume no Mata Yume no Mata Yume
https://www.fakku.net/doujinshi/manatsu-no-yoru-no-yume-no-mata-yume-no-mata-yume-japanese
gender bender
LOVEkyon
https://www.fakku.net/doujinshi/lovekyon-japanese
gender bender
KYO-N wa Kanojo na no ka
https://www.fakku.net/doujinshi/kyo-n-wa-kanojo-na-no-ka-english
gender bender
KYO-N wa Kanojo na no ka
https://www.fakku.net/doujinshi/kyo-n-wa-kanojo-na-no-ka-japanese
gender bender
Haru na no ni Sukumizu de Iin Desu ka
https://www.fakku.net/doujinshi/haru-na-no-ni-sukumizu-de-iin-desu-ka-english
gender bender
Haru na no ni Sukumizu de Iin Desu ka
https://www.fakku.net/doujinshi/haru-na-no-ni-sukumizu-de-iin-desu-ka-japanese
gender bender
I know that seems like a lot, but considering the amount of gender bender doujinshi that exists, it's actually pretty short.
There is also Ranma 1/2 and Naruto, which I haven't gone through.
A few more tags to consider adding are: body swap, henshin (transformation), and cross dressing, though I can't think of any in particular doujin at the moment.