Free Software for macOS
QGIS
QGIS is a free and open-source software that can be used access planetary imagery and geospatial data. The platform is openly developed and released under the GNU GPLv2. With QGIS, users can view, edit and analyse geospatial data cross-platform, for Android, macOS, Linux and Windows.
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.
LispPad
LispPad is a simple, lightweight, IDE for developing and running Scheme code on macOS. The language supported by the integrated development environment LispPad is based on the R7RS (small) standard of the Scheme programming language. LispPad provides the a wide range of components inclduing a fully integrated Scheme interpreter, a large set of libraries, a text editor supporting syntax highlighting, smart indentation, parenthesis matching and text completion.
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.
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.
Ultimaker Cura
Ultimaker Cura is a free 3D printing software that is used by millions of users worldwide. The software is an advanced slicing engine that can be used to prepare your 3D models in a few clicks, and then easily send of to the printer, and get job done.
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