BareFolk Horse Bristle Toothbrush
approx. €4-6
Best available material compromise: bamboo handle, horse-hair bristles, no nylon or petroleum bristles, no plastic, and a very low price.
Animal-welfare sourcing is not farm-level transparent. Buy for the material advantage, not because the ethical story is fully proven.
A European (EU) source in the The Unmasked Face directory, chosen so it can actually be bought and shipped from Central Europe.