Code2Flow - An easy solution to create product flows.
Shared Spotify - Find the common songs you have between friends
asciiflow - Infinite ASCII diagrams, save to Google Drive, resize, freeform draw, and export straight to text/html.
Spotify Codes - Share codes for songs, artists, and playlists from Spotify
Flowchart.js - Draw SVG flow charts from simple text representations of the diagrams.
Bands on a Budget - Economical SWAG meant for bands, often hijacked by startups