Backup & Sync
In life, things happen. It’s the nature of the beast. Fires, floods, robbery, and other disasters that can rob you of data occur with some amount of regularity. This means that it’s critical to have a backup or contingency plan in order to pick up where you left off the best you can in case the worst case occurs. That’s where software focused on backing up and synchronizing your data comes in. Software that focuses on backing up physical media, local hard drive data, and even critical messages and other forms of communication is the focus here, alongside services such as DropBox and OneDrive that focus on constantly syncing data between your devices and secure external servers that you can access from anywhere with an Internet connection.Most popular apps
7-Zip
7-Zip is a file archiver with a high compression ratio.The main features of 7-Zip High compression ratio in 7z format with LZMA and LZMA2 compression
Dropbox
Worlds leading online storage and file sync service. You get 2GB free. Apps for all major platforms.
Inkscape
Inkscape is a professional vector graphics editor for Linux, Windows and macOS. It's free and open source.
Google Drive
Google Drive is a file storage and synchronization service which enables user cloud storage, file sharing and collaborative editing.
Nextcloud
A safe home for all your data – Access & share your files, calendars, contacts, mail & more from any device, on your terms.
calibre
Calibre is a free and open source e-book library management application made by users, for users. Many languages, designed around the concept of the logical book, i.e.
Google Keep
Google Keep has several features including color coding notes, inserting images, creating lists, geo-fencing, shareable notes, and search by color.
MEGA
MEGA, the successor of 
MegaUpload , is a cloud storage and file hosting service produced by Mega Limited.
Transmission
Transmission has the features you expect in a BitTorrent client: encryption, a web-based interface, peer exchange, UPnP and NAT-PMP port forwarding, web seed support, watch...