twcbackup is easy-to-configure backup software with a graphical configuration tool. It supports multiple backup methods. Usually, the bfsync method is used, which maintains a backup pool of SHA1-hashed files which allows file-level duplication. Automatic deletion of old backups, backup of local data or remote machines via ssh/rsync (Linux machines) or smb/rsync (Windows machines), and replication of the backup repository are supported.
NouvaLinux backup and rescue is a live CD with some special tools for making backups and system recovery. The main tool is an application made by RyXéo (a free software company): a partclone GUI. Backup is Clonezilla compatible: you can make backups with NouvaLinux backup and restore them with Clonezilla.
SnaRSShE (Snapshots via Rsync in a Simple Shell Environment) is a simple, lightweight (both in size and system requirements) server data archiving package designed for secure and reliable archiving of critical data of defined network systems. The general idea was taken from the need to capture snapshots of data on a regular basis and have easy access to that data. Originally, the script handled alerting as well, but the author since recognized the sense in offloading the alerting to a separate system. This script is a front-end for rsync, which does the real work. SnaRSShE just creates the environment and manages the rotation of archives.
Shasplit takes a large data block, splits it into smaller parts, and puts those parts into an SHA-based content-addressed store. Reassembling those parts is a trivial "cat" invocation. Repeating parts (e.g., from previous split operations) are stored only once, which allows efficient incremental backups of whole LVM snapshots via Rsync. Shasplit shows its strengths on encrypted block devices, but might be useful for non-encrypted data, too.