Recs if you like The King's Captive...

Limiting this to fantasy/sci-fi, these are books where the MCs are locked up for most of the book or it's a crucial part of the plot. This can include magical prisons, cursed towers, institutions of sorts, and probably more!

Urban worlds with some ethically sourced chaos. A collection of indie urban fantasy books full of magic and the paranormal.

in which a shifter-character is mistaken for a normal animal and treated accordingly

may also include non-humans (eg. aliens) not realising humans are sentient and keeping them like literal pets