The main theme is sexual bondage.
This is the Yaoi (BL), Bara (ML) and Yuri (GL) version of this list. It’s still a work in progress.Warning: Some of these feature really heavy S&M, or might include non-con, confinement, etc.
Here is the straight version of this list: ⛓️Bondage, BDSM⛓️ (straight).