If you want more storage for your work, a Premium Lovely Charts accounts (which costs about $46 per year) lets you save unlimited diagrams, export to PDF, import your own artwork, share your ...

Flow charts may include different levels of detail as needed, from a high-level overview of an entire system to a detailed diagram of one component process within a larger system.

Lovely Charts is a free web-based tool for creating flow charts, site maps, network diagrams, and other visualizations with a drag-and-drop interface ...

If you are not familiar with Visio, it's used for creating diagrams such as flow charts and network diagrams. What I didn't realize is that you can actually create Visio diagrams from within Excel.