There are 2 repositories under android-backup topic.
Backup Android SMS, MMS and call log to Gmail / Gcal / IMAP
Back up your device without vendor lock-ins, using insecure software or root. Supports encryption and compression out of the box. Works cross-platform.
A customizable Android and iOS/iPadOS WhatsApp database parser that will give you the history of your WhatsApp conversations in HTML and JSON. Android Backup Crypt12, Crypt14, Crypt15, and new schema supported.
Simple android application to extract SMS from device into CSV file
Demo app for demonstrating a way of backup user data
This tool allows you to recover apps data from a TWRP-compatible backup
A simple script to backup an Android phone on Arch Linux.
Simple Shell script to backup and restore apk on Android
Kaslo is a GUI application that help you backup android partitions like system.img, boot.img...
Codelab code on how to backup your Android app data.
Unpacks ".ab" Android backups made using adb backup into regular ".tar" archives.