Sheetson - Instantly turn any Google Sheet into RESTful API
Sheet 2 Site - Generate a website from 📗 Google Sheets
Stein - Use Google Sheets as your no-setup database
Sheety - Turn any Google sheet into an API instantly, for free. Power websites, apps, or whatever you like, all from a spreadsheet. Changes to your spreadsheet update your API in realtime. Neat
Sheetsu - Turn Google Spreadsheet into API
Dropbase by Castodia - Turn your CSV files into live databases in seconds