[ThatCaio]

Yes, Tolman–Oppenheimer–Volkoff limit would estimate a star around 1.5-2.5 sun masses could result in a stellar black hole.

We don't know much about stars collapsing, and the mass wasted in the process to have a more accurate number at this point.

[ejolto]

That's only true for black holes created from the collapse of stars. Primordial black holes would have been created in the early universe and be much much smaller.