According to Wikipedia, which cites a sefer of takanot by the Toldot Aharon Rebbes, chassidim of that sect do not wear wool, for fear of shaatnez. If this is the case, what material are their tallitot and tzitziot made from?
They are still woolen. Since tallitot and tzitziot are under strict supervision, they are (wrongly?) assumed to be safe.
Source: My uncle, a Toldos Aharon chassid.