Cool Reader is a powerful and lightweight reader for Android that lets you open practically any type of text document on your device. The app supports the following file types: fb2, doc, txt, rtf, html, chm, tcr, pdb, prc, mobi and epub (without DRM).
Cool Reader stands out for many reasons, such as its small size (just over 6 mb) and its many possibilities when it comes to displaying books on your Android device. However, its most interesting feature is that it not only opens text documents, it also lets you directly access pages such as The Gutenberg Project and The Internet Archive, to quickly download and display some of the most popular books of all time.
Cool Reader is a powerful document and digital book reader, yet still has a simple and accessible interface. It's only shortcoming is perhaps that its style is a bit ugly and outdated.