For most WebGL a 4x4 matrix multiply is all thats needed. GLSL will implement the basics. But all the 3D libraries include matrix ops: threejs, babylon, etc. Then there are standalone math libs like glMatrix and math.gl from Uber. There is even a WebAssembly accelerated library: glmw.

Just really curious what sort of simulations or applications one would build with an in-browser BLAS implementation ;)