Appium is an open source test automation tool for use with native and hybrid mobile apps. It drives iOS and Android apps using the WebDriver JSON wire protocol. Appium aims to automate any mobile app from any language and any test framework, with full access to back-end APIs and DBs from test code.
Lettuce is a very simple BDD tool based on the Cucumber. It provides to the developers the ability of describing features in a natural language, by creating one or more scenarios. Each scenario has one possible behaviour of the feature you want to implement. To make the scenarios run python code, it is necessary to define steps.
Sikuli is a visual technology to automate and test graphical user interfaces (GUI) using images (screenshots). Sikuli includes Sikuli Script, a visual scripting API for Jython, and Sikuli IDE, an integrated development environment for writing visual scripts with screenshots easily.