Free Software for macOS
Tor
Tor is free and open-source software and network that enables anonymous communication and browsing. Tor can be used to defend yourself from aggressive tracking, surveillance and censorship and provides a good base for anonymity online. The name Tor is derived from the original project name "The Onion Router".
Termius
Termius is the SSH client that works on both Desktop and Mobile. The application lets you organize hosts into groups while allowing share settings across users. Terminus uses end-to-end encryption to ensure your data remains safe and secure, while keeping connection and command history.
Irssi
Irssi is a terminal based IRC client for UNIX-based operating systems. Irssi comes with IRC built-in and is multi-protocol friendly for module authors, it also support integration with SILC and ICB protocols via plugins. The application easily integrates with your window manager, your terminal emulator, your remote connection, your terminal multiplexer, your IRC bouncer and your IRC adapter. Allowing you to use Irssi virtually everywher throughout your system. Irssi is free software licensed under the GPLv2, available for macOS, Linux, BSD, Solaris, and Cygwin.
FlexGet
FlexGet is a free and open-source multipurpose automation tool for all of your media with support for torrents, nzbs, podcasts, comics, TV, movies, RSS, HTML, CSV, and more.
Shotcut
A free and openly developed video editing software that works cross-platform. Shotcut is developed on the MLT Multimedia Framework and is avalible for FreeBSD, Linux, macOS and Windows. Shotcut is released as open-source software under the GPLv3.
LibreOffice Calc
LibreOffice Calc is a free and open-source spreadsheet tool part of the LibreOffice software package. With LibreOffice Calc users can manage spreadshets with its native Open Document Format (.ods), CSV (.csv) and other common formats like the Microsoft Excel format. The software is openly developed by The Document Foundation and the open source community while being released under a combination of license including MPLv2.0 and a secondary license GPL, LGPLv3+ or Apache License 2.0.
USBImager
A really simple open-source, GUI application that writes compressed disk images to USB drives and creates backups. USBImager is avalible for Linux, macOS, and Windows.
RedisGraph
RedisGraph is the first free and open source queryable Property Graph database to use sparse matrices to represent the adjacency matrix in graphs and linear algebra to query the graph.
Apple Siri
Apple Siri is a virtual assistant that is part of Apple's ecosystem of operating systems, including iOS, iPadOS, watchOS, macOS, and tvOS.