As many readers know, H1B status holders in the US, may apply for visa stamp in Canada. This way avoiding a costly trip the country of origin. Such applicants are called Third Country Nationals.
The US Consulate General in Cananda ACCEPTS the following types of NIV applications from Third Country National (TCN) applicants:
Applicants seeking to renew their C1/D, D, E , F, H (except H-2), I, J, L, M, O, P and R visas, regardless of where the original visa was issued. Certain visa applicants may be subject to additional administrative processing.
Visa Lawyer Blog

