1. WinDjView is a fast, compact and powerful DjVu viewer for Windows with tabbed interface, continuous...

  2. MuPDF is a lightweight PDF and XPS viewer.

  3. Open Source PDF Viewer for Android based on MuPDF library

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

  5. Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.

  6. A simple and modern eBook viewer.

  7. Read CHM is ultimate CHM (Compiled HTML Help) file reader.

  8. CHM Reader Pro is can read CHM file and Convert CHM to PDF.

  9. A fully featured reader for Compiled HTML (chm) documents.

  10. xCHM is a cross-platform GUI front-end to chmlib, with borrowed bits from Pabs' chmdeco project.

  11. Easy-to-use tabbed style ebook reader, equipped with library shelf, supports popular ebook formats...

  12. Librera Reader for Android