Okular - Okular is a universal document viewer based developed by KDE.
VoiceMaker - Voicemaker is a web application with which you can convert your texts into audio by simply importing the text onto the dedicated text box.
Sumatra PDF - Sumatra PDF is a slim PDF/DjVu/EPUB/XPS/CHM/CBR/CBZ/MOBI viewer for Windows.
Notevibes - Online Text to Speech Converter with 57 natural voices. Download your files as mp3 and Wav. For business and personal usage.
Foxit Reader - Foxit Reader is a free and light-weight multi-platform PDF document viewer.
Free TTS - Free TTS is a web application that can convert any text into audio.