Yes. You can sell as many different products from as many different suppliers as you like.
If you are currently using other print-on-demand, dropshipping, or fulfillment services, you can still install and utilize Spreadconnect. Spreadconnect only interacts with Spreadconnect-specific SKUs and will not affect other products, giving you the opportunity to enjoy our speed, quality, and services at no risk to your other products or provider's interactions.