Sigil - Sigil is a multi-platform WYSIWYG ebook editor. It is designed to edit books in ePub format.
Jutoh - Epub editor, convertor and creator software for Mac and PC.
WLPPR - Beautiful mobile wallpapers made from satellite imagery
calibre - Ebook manager, viewer & converter
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
To EPUB - Instantly convert text documents and ebooks to EPUB format with this free online EPUB converter.