Sheetsu - Turn Google Spreadsheet into API
Neonto - Visual tool for creating native iOS and Android UIs
SpreadSimple - A blazing-fast way to create and manage sites using Google Spreadsheets
Rainbow Pencils - Make rainbows whenever you sharpen.
SheetAside - Access your Google Sheets from where you are
Creo - Creo is a modern design tool for Mac which combines design and development.