Hostage, Mob for Jack, and Hua Hua You Long are my favorites ⁄(⁄ ⁄·⁄ω⁄·⁄ ⁄)⁄
http://www.mangago.me/tag/Stockholm+syndrome/?page=1
http://www.mangago.me/read-manga/running_on_empty/ maybe not completely true Stockholm syndrome but its kinda what you usually think of..plus its pretty cute.
https://www.mangaupdates.com/series.html?id=54668
https://www.mangaupdates.com/series.html?id=8665
Any manga shoujo/josei or yaoi about stockholm syndrome?