Adobe Reader

Okular is a universal document viewer based on KPDF for KDE 4 with support for advanced document features, such as annotations, forms, and embedded files. Okular combines the excellent functionalities …

With GoodReader on your iPhone, iPod Touch or iPad, you can read virtually anything, anywhere. Books, movies, maps, pictures; GoodReader puts it all in a single app, right in your …

EBookDroid is an open source (GPL'ed) document viewer for Android based on the VuDroid code base. Supported the file in following formats: PDF DjVu XPS (OpenXPS) comics books (cbz,cbr) ...

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

Open Source PDF Viewer for Android based on MuPDF library

qpdfview is a Qt-based tabbed document viewer using the Poppler library for PDF rendering and CUPS for printing. Support for the DjVu and PostScript formats can be added via plugins.

Xpdf is an open source viewer for Portable Document Format (PDF) files. (These are also sometimes also called 'Acrobat' files, from the name of Adobe's PDF software.) The Xpdf project …

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.

A free PDF reader.