Quote - Is there something like "show all by this vendor", I can't seem to pull that off.

Click on the "Shop by Artist" button, then pick a vendor.

The other advantage of brokering via Renderotica, is that there is no "Clearance" section like there is here, so once the initial rush of sales is over, items remain in the store with no need to worry about them being forced out due to lack of sales.