Cross-platform software
Within computing, cross-platform software is computer software that is designed to work in several computing platforms. Some cross-platform software requires a separate build for each platform, but some can be directly run on any platform without special preparation, being written in an interpreted language or compiled to portable bytecode for which the interpreters or run-time packages are common or standard components of all supported platforms. (Wikipedia)
Free software
Free and open-source software (FOSS) is software available under a license that grants users the right to use, modify, and distribute the software. Free software, libre software, libreware sometimes known as freedom-respecting software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, distribute it and any adapted versions. Free software is a matter of liberty, not price; all users are legally free to do what they want with their copies of a free software regardless of how much is paid to obtain the program. (Wikipedia)
XnView MP https://www.xnview.com/en/
image viewer, photo management, and image resizer software
Gimp http://www.gimp.org
Gimp – vs – Photoshop https://expertphotography.com/gimp-vs-photoshop/
Rawtherapee https://www.rawtherapee.com
Like Camera RAW image converter and processing software
Like Photoshop-CS
Darktable http://www.darktable.org/
Like Adobe lightroom
Krita https://krita.org/
Like Corel Painter Adobe Photoshop
Inkscape https://inkscape.org
Like: Adobe Illustrator; CorelDraw; Affinity Designer
Blender http://www.blender.org/
Like Maya
Scribus https://www.scribus.net
Like Quarkxpress; InDesign MS Publisher
Kdenlive https://kdenlive.org/
Like Adobe Premiere Pro
OpenShot https://www.openshot.org
Like Simple Video editing software
Handbrake https://handbrake.fr/
Like video ripper and transcoder software
LMMS http://lmms.io/
Rosegarden https://www.rosegardenmusic.com/
Audacity https://www.audacityteam.org/
Frescobaldi http://www.frescobaldi.org/
MusicBrainz Picard https://picard.musicbrainz.org
Clementine http://www.clementine-player.org/
WPS Office https://www.wps.com/en-US/
Like MS Office
Libre Office http://www.libreoffice.org
Like MS Office
Dia https://wiki.gnome.org/Apps/Dia/
Like UML editor Ckt Diagram Ms Visio
Accounting / Book Keeping
GnuCash https://gnucash.org/ Like quick books
Portfolio Performance
Biogenesis http://biogenesis.sourceforge.net/
Ugene https://ugene.net
