Orion Viewer!

Foxit Reader is a free and light-weight multi-platform PDF document viewer. Its core function is compatible with PDF Standard 1.7.

MuPDF is a lightweight PDF and XPS viewer.

Are you tired from many viewers one for each document?Do you want to have, one program for all your technical documentations, scientific books and so on?Do you want to have program, which fast opens files, fast loads pages and fast renders page to screen?And all of this in free software?

It is an all-in-one solution to read and manage your eComic library. You can think of it as ITunes for eComics with much of the same functionality.

WinDjView is a fast, compact and powerful DjVu viewer for Windows with tabbed interface, continuous scrolling and advanced printing options. It uses the free DjVuLibre library to decode DjVu documents. DjVu is a web-centric format and software platform for distributing documents and images.

A fork of the last GPL version of EBookDroid. Supports the following formats:

EBookDroid is an open source (GPL'ed) document viewer for Android based on the VuDroid code base.

Xodo is the ultimate cross-platform PDF viewer and annotator. And it’s 100% free.

Besides exceptionally fast launching and displaying speed, Gaaiho Reader is reliable in printing, filling forms annotating documents and adding bookmarks.

qAllInOne (aka qAIO) is a free open-source software built using Qt to provide users an All-In-One media player, so it can view images, play videos and audio.

With Google Docs Viewer, you can quickly view many file types online, including PDFs, Microsoft Office files, and many image file types.

The application allows you to directly open and read PDF files that have been saved to your media card – without the need for server-side conversion, services or subscriptions.

BePDF is a PDF viewer for the BeOS, Haiku & Zeta.Besides viewing, it supports annotating and user-defined bookmarking for unencrypted PDFs. It's fully localized for 20 languages at the moment with additional languages being easily added via text files.

The Flipping PDF Reader allows to read PDF documents in user friendly interface with flipping book effect. Good looking and convenient alternative for Adobe PDF Reader.