For a pairing lacking in canon interaction there are surprisingly a few doujins out there! This is a list of published SasuHina doujinshi & anthologies. Only physical books will be listed here. (May eventually make a separate section for digital work.)
Title: ねむりの森 (Nemuri no Mori)
Circle: en・樹 （えんじゅ)
Artist: Kou Takamura
Pages/Size: 40 ~ B5
Published: 29.12.2005
Title: 覚醒 (Kakusei)
Circle: en・樹 （えんじゅ)
Artist: Kou Takamura
Pages/Size: 32 ~ B5
Published: 29.12.2005
Title: スプリング·エラ— (Spring Era)
Circle: 『UNKNOWN』
Artist/Writers: なるは | Sagami | RON
Pages: 46 (?)
Published: 17.06.2014
Title: 行至未尽 (Endless Journey)
Author: 听水君
Pages/Size: 310 ~ A5
Published: 22.10.2020
Read: English translation on FF.net
Title: Stella 34 And Other Stories
Artist: Tofuparart
Pages/Size: 180 ~ 4.25 x 6.88 in
Published: 26.07.2015
Availablity: Read Online || Purchase