We should come up with some different names.
I think the implementation that is currently the fastest should get the name matmul!. IIRC, PaddedMatrices currently has the fastest implementation. So we should keep the name matmul! for PaddedMatrices, and come up with a different name for Octavian.jl. Maybe gemm!? Or matrix_mul!?
For reference, the LinearAlgebra standard library exports the following names, so we should not export any of them from our own packages:
axpby!
axpy!
lmul!
mul!
rmul!