The Ultimate Google Sheet Toolkit - We put together a curated list of templates, videos, and tutorials that can help you build your analytics expertise.
Algo by AirDev - Turn a Google Sheet model into a web app in 5 minutes
MadKudu for Google Sheets - Get predictions about your target market in GSheets for free
SpreadShare - Explore community-curated spreadsheets.
SyncWith for Google Sheets - Data from any app into Google Sheets, reports & dashboards
Sheetsu - Turn Google Spreadsheet into API