Tea

These are the first ones that came to my head, it's really hard to find Doujinshi of Haikyuu characters aged up so the different ships/pairings are very limited. I hope this helps, Happy Reading!!! <3

Iwaizumi x Oikawa
(Anything by Gusari is PURE PERFECTION, and as you can tell I love IWAOI)
http://www.mangago.zone/read-manga/haikyu_dj_tonari_no_fukanou_to_koufuku/mf/c001/ http://www.mangago.zone/read-manga/haikyu_dj_uramado_dogfight/mf/c001/
http://www.mangago.zone/read-manga/haikyu_higan_no_kagee_doujinshi/
http://www.mangago.zone/read-manga/haikyu_dj_tanoshii_jogoku_wo_irodoru_nara/
http://www.mangago.zone/read-manga/haikyuu_dj_kono_machi_ni_sunderu_karera_no_koto/
http://www.mangago.zone/read-manga/haikyu_dj_gunjou_no_shashin/mi/mi_chapter-1/
http://www.mangago.zone/read-manga/iwachan_no_neko_ni_naritai_7_haikyuu_dj/


Kuroo x Tsukishima
http://www.mangago.zone/read-manga/haikyuu_dj_vow/
http://www.mangago.zone/read-manga/haikyuu_dj_937_boost/mi/cfc613bcc6c498f01874a840a9ae3fe1_chapter-1/
http://www.mangago.zone/read-manga/lazy_lazy_night_haikyuu_dj/

Akaashi x Tsukishima
http://www.mangago.zone/read-manga/over_work_haikyuu_dj/

Bokuto x Akaashi
http://www.mangago.zone/read-manga/haikyuu_affair_after_the_tonight/hs/hs_chapter-1/

Kuroo x Tsukishima and Bokuto x Akaashi
http://www.mangago.zone/read-manga/hito_wa_sore_o_shitto_to_yobu_haikyuu_dj/

Kuroo x Daichi (I had NO idea people shipped them)
http://www.mangago.zone/read-manga/the_coward_s_red_string/uu/the_coward_s_red_string-chapter-1

Ukai x Takeda (I'm so sorry for this one but like you DID say "aged up so" :/)
http://www.mangago.zone/read-manga/haikyu_dj_sake_wa_horoyoi_hana_wa_tsubomi/
http://www.mangago.zone/read-manga/haikyu_dj_weekend_rendezvous/
http://www.mangago.zone/read-manga/haikyuu_dj_sensei_ti_issho/

These are the first ones that came to my head, it's really hard to find Doujinshi of Haikyuu characters aged up so the different ships/pairings are very limited. I hope this helps, Happy Reading!!! <3

Iwaizumi x Oikawa
(Anything by Gusari is PURE PERFECTION, and as you can tell I love IWAOI)
http://www.mangago.zone/read-manga/haikyu_dj_tonari_no_fukanou_to_koufuku/mf/c001/ http://www.mangago.zone/read-manga/haikyu_dj_uramado_dogfight/mf/c001/
http://www.mangago.zone/read-manga/haikyu_higan_no_kagee_doujinshi/
http://www.mangago.zone/read-manga/haikyu_dj_tanoshii_jogoku_wo_irodoru_nara/
http://www.mangago.zone/read-manga/haikyuu_dj_kono_machi_ni_sunderu_karera_no_koto/
http://www.mangago.zone/read-manga/haikyu_dj_gunjou_no_shashin/mi/mi_chapter-1/
http://www.mangago.zone/read-manga/iwachan_no_neko_ni_naritai_7_haikyuu_dj/


Kuroo x Tsukishima
http://www.mangago.zone/read-manga/haikyuu_dj_vow/
http://www.mangago.zone/read-manga/haikyuu_dj_937_boost/mi/cfc613bcc6c498f01874a840a9ae3fe1_chapter-1/
http://www.mangago.zone/read-manga/lazy_lazy_night_haikyuu_dj/

Akaashi x Tsukishima
http://www.mangago.zone/read-manga/over_work_haikyuu_dj/

Bokuto x Akaashi
http://www.mangago.zone/read-manga/haikyuu_affair_after_the_tonight/hs/hs_chapter-1/

Kuroo x Tsukishima and Bokuto x Akaashi
http://www.mangago.zone/read-manga/hito_wa_sore_o_shitto_to_yobu_haikyuu_dj/

Kuroo x Daichi (I had NO idea people shipped them)
http://www.mangago.zone/read-manga/the_coward_s_red_string/uu/the_coward_s_red_string-chapter-1

Ukai x Takeda (I'm so sorry for this one but like you DID say "aged up so" :/)
http://www.mangago.zone/read-manga/haikyu_dj_sake_wa_horoyoi_hana_wa_tsubomi/
http://www.mangago.zone/read-manga/haikyu_dj_weekend_rendezvous/
http://www.mangago.zone/read-manga/haikyuu_dj_sensei_ti_issho/

thank u for listing soo many thats so sweet of u two (≧∀≦)