You can sell third brands of third party on another website by contacting online market. It calls aggregator business. You can sell your own brands if you wish. If you take interest in designing then you can apply it on other products. You can print your designs on products. Inkfruit.com is implementing such ideas. Here you can sell your own designs. Company prints these designs on t-shirts, cups, calendars, hats, bags, books, posters, greetings etc.
If you want to make money with online branding then make a google search with keywords “sell stuff online” “affiliate market” “online branding” or “sell designs online” etc.