You should be familiar with US-based Newegg which is enjoying success on the other side of the Atlantic and is increasingly gaining international traction. We wrote about the main Newegg marketplace here as part of the Marketplaces 2018 series. Crucially when dealing with Newegg, remember that it acts as the “merchant of record”, meaning that you will have no liability regarding US sales tax.
The Neweggbusiness marketplace is significantly smaller but offers a special audience of buyers that they characters as firms large and small, education establishments, government bodies, healthcare providers, organisations in the nonprofit sector and system integrators. They claim to have roughly 350k buyers on the marketplace.