When it comes to shota always PWP PORN.JUST PORN.

tis indeed difficult to find non-porny shotacon. but there are a few.

http://www.mangago.zone/read-manga/inaka_ni_kaeru_to_yakeni_jiben_ni_natsuita_kasshoku_ponytail_shota_ga_iru/


http://www.mangago.zone/read-manga/sayonara_alpha/ (sex eventually happens, but after he grows up)


http://www.mangago.zone/read-manga/my_little_vampire/ (dunno if this counts but he is a kid for a little while and the sex comes only after he grows up)


http://www.mangago.zone/read-manga/super_lovers/


http://www.mangago.zone/read-manga/himitsu_no_akuma_chan/ (not exactly shotacon but kinda close)


http://www.mangago.zone/read-manga/catboy_catday/


also pretty much every shotacon that isnt BL


there's also more, but I'm to lazy to find them all...most are one-shots cause shotacon is kinda hard to find as an actual series.