Vegan condoms and sex toys are made without casein or other animal-based byproducts.
Fun fact: a lot [2] of consumer goods use animal-based byproducts either as technical agents (e.g. beer that's being filtered through fish bladders) or as outright ingredients (shampoo, perfume, ...).
[1] https://www.greencondom.club/vegan
[2] https://www.onegreenplanet.org/animalsandnature/products-you...