MPlayer
MPlayer – free and open source, cross-platform media player
QMPlay2
QMPlay2 – free and open source, multiplatform video and audio player which can play most formats and codecs
Celluloid
Celluloid – free and open source, simple media player that can play virtually all video and audio formats, GTK+ frontend for mpv
SMPlayer
SMPlayer – free and open source media player with built-in codecs, with support for Youtube for Windows and Linux
FreeFileSync
FreeFileSync – free and open source data backup software that helps you synchronize files and folders
Grsync
Grsync – free and open source program for syncing folders, files and creating backups, GTK GUI for rsync
luckyBackup
luckyBackup – free and open source, powerful, fast and reliable backup and sync tool
syncBackup
syncBackup – free and open source program for synchronization and backup data (GUI rsync)
Timeshift
Timeshift – free and open source software for creating snapshots of the file system
Deja Dup
Deja Dup – free and open source simple backup tool with compression and encryption capabilities from GNOME for Linux