Adobe Reader -> SumatraPDF http://blog.kowalczyk.info/software/sumatrapdf/free-pdf-reader-es.html

Microsoft Office -> LibreOffice 
www.libreoffice.org/


Adobe InDesign -> Scribus 
http://www.scribus.net/canvas/Scribus

Windows Media Player/Kool Player -> Video Lan Client
http://www.videolan.org/vlc/

Audio Player -> Clementine 
http://www.clementine-player.org/en/

WinRAR -> 7zip
http://www.7-zip.org/

Skype->JitSi
https://jitsi.org/

Internet Explorer -> Firefox
http://www.mozilla.org/es-ES/firefox/new/

Nero Burning Rom -> InfraRecorder
http://infrarecorder.org/

µtorrent -> qBitTorrent
http://www.qbittorrent.org/

VmWare -> VirtualBox
https://www.virtualbox.org/

Maya3D -> Blender
http://www.blender3d.org/

Photoshop -> Pinta
http://pinta-project.com/