Pennywise - Cross-platform application to open any website or media in a floating window
SellerCloud - SellerCloud is a multi-channel inventory and order management system.
PiP for Mac - Always on top window preview similar to the popular windows only OnTopReplica
Sellbrite - Multichannel ecommerce management for serious sellers.
Shopify - Shopify is a powerful ecommerce platform that includes everything you need to create an online store and sell online. Try it free for 14 days.
Webgility - Accounting, Bookkeeping and Inventory Automation for Retailers & Brands