BorgBackup (short: Borg) is a deduplicating backup program. Optionally, it supports compression and authenticated encryption.

Rclone (" rsync for cloud storage") is a command-line program to sync files and directories to and from different cloud storage providers.

Pika Backup is designed to save your personal data and does not support complete system recovery. Pika Backup is powered by the well-tested BorgBackup software.

restic is a program that does backups right. The design goals are: Easy, Fast, Verifiable, Secure, Efficient, Free.

For simple e-mail, looks a lot cleaner than Thunderbird. But missing some advanced features.

Written in C, much faster and more lightweight than Thunderbird/Betterbird. But not cross-platform. Thunderbird you can copy profiles over to mobile or Windows if you want. Otherwise, Evolution would be superior.

Good, but if you aren't using KDE, it's a bit bloated as you don't have everything already from the OS.

This or thunderbird is still the best for more complicated functions with email, such as using Resend aliases, etc.

Open source desktop app integrating messaging, email, productivity tools and custom services with workspaces, Todo panel, privacy features, resource saving and sync.

An encrypted messaging app focused on privacy, supporting texts, calls, photos, videos, files, and group chats, with no ads or trackers.

Experience instant messaging with remarkable speed and robust security. Join massive group chats or channels. Enjoy free and advanced features.

A secure collaboration app with end-to-end encryption and interoperability across web, desktop, and mobile. Includes chat, voice, and video calls.

HexChat is an IRC client based on XChat for Linux , but unlike XChat it’s completely free for both Windows and Unix-like systems.

Use as plugin with OCRmyPDF to add lightweight support for more complicated page layouts.

OCRmyPDF adds an OCR text layer to scanned PDF files, allowing them to be searched - jbarlow83/OCRmyPDF

Better Word support than libre, and faster than word (and you can easily write JS plugins).

Sophisticated text editor for code with sleek interface, multi-select tabs, side-by-side definitions, and swift variable renaming using multiple selections.

An end-to-end encrypted note-taking by Proton. Offline access, unlimited sync across devices, tagging, passcode and biometric security, plus advanced premium privacy features.

Blazing fast, collaborative code editor with real-time multi-user support, built-in Vim mode, language-aware syntax trees, integrated terminal, and multi-buffers.

Flatseal is a graphical utility to review and modify basic permissions from your Flatpak applications.

Faster than devbox, combined with Distrobox for atomic linux

Use any Linux distribution inside your terminal. Enable both backward and forward compatibility with software and freedom to use whatever distribution you’re more comfortable with. Distrobox uses podman or docker to create containers using the Linux distribution of your choice.

For creating more lightweight environments than distrobox, such as when coding. Very similar to python's venv.