I also thought of new objects, etc …
Animal / creature eggs which will automatically give an animal / creature, but they are quite expensive, rarely drop, and will last long enough (15 days for example) before giving the animal / creature.
Arrows, vial, etc … with a poison which puts to sleep to facilitate the captures.
more animals and creature, like wolves, bears, harpy, etc …
ghosts, orcs, goblin, undead, etc … will not be able to be tamed, but apart from ghosts and undead, the rest can be captured
capture-related events, such as escape attempts, which can lead to forced combat (mainly with orcs and goblins).
creatures / animals will have a higher or lower taming percentage .. eg the spider will be easier to tame than the troll.