Glimpse

Glimpse is the open source answer to Adobe Photoshop. You might be thinking 'I thought that's what GIMP was. And you would be right. Glimpse is a GIMP fork. The change of name will make it easier to recommend to students without having to deal with the sniggers that GIMP receives.

Krita

Krita is a professional FREE and open source painting program. It is made by artists that want to see affordable art tools for everyone.This is a one of those addictive programs that once mastered will give the user a powerful tool to create digital art.

Inkscape

Inkscape is a Free and open source vector graphics editor for GNU/Linux, Windows and MacOS X. It offers a rich set of features and is widely used for both artistic and technical illustrations such as cartoons, clip art, logos, typography, diagramming and flowcharting. It uses vector graphics to allow for sharp printouts and renderings at unlimited resolution and is not bound to a fixed number of pixels like raster graphics. Inkscape uses the standardized SVG file format as its main format, which is supported by many other applications including web browsers.

Audacity

Audacity is a free, easy-to-use, multi-track audio editor and recorder for Windows, macOS, GNU/Linux and other operating systems. It can be used for live recordings and editing. This is the ideal tool for budding Podcasters and sound editors. Use it for cutting, splicing, converting and much more.

Ardour

Ardour's core user group: people who want to record, edit, mix and master audio and MIDI projects. When you need complete control over your tools, when the limitations of other designs get in the way, when you plan to spend hours or days working on a session, Ardour is there to make things work the way you want them to. Ideal for anyone who needs a Digital Audio Workstation

LMMS

Another awesome piece of software aimed at music creators. it allows music to be produced by arranging samples, synthesizing sounds, playing on a MIDI keyboard, and combining the features of trackers and sequencers.

OpenShot

Award winning open source video editing software. Create stunning videos at the clock of a button. Simple and intuitive to learn, yet powerful features will give professional quality results.

Shotcut

Free and open source video and audio editing software. The website even has tutorials and resources for you to use.

OBS Studio

Open source yet professional software for video recording and live streaming. This is the software for those needing to produce a live broadcast or producing a recording. Highly esteemed by youtubers and other video streamers.

Libre Office

This is the Open Source world's answer to Microsoft Office. It includes high quality Word processor, Slideshow creator and viewer, Spreadsheet and much more. What's more, it's has high compatibility with MS word.

OnlyOffice

This is a fantastic project which has a desktop version (good for most people) and a server version, so it can be deployed to a server for cloud access. It's got a great suite of tools, again like Office 365, it has a highly compatible word processor, slideshow maker and spreadsheet creator. This is free to use, but there are options for hosting this product which are paid for.

WPS Office

Open source yet professional software for video recording and live streaming. This is the software for those needing to produce a live broadcast or producing a recording. Highly esteemed by youtubers and other video streamers.

Google Colaboratory

For Python programming. SOOOO handy for teachers to be able to view and comment on students work while we are in this era of ELearning.
Colab gives us a Python text editor and runtime environment in one package. The ideal place for practicing and learning Python. Though I would say it is not for anyone who is creating a serious project.
All you need is a Google Account

Thonny

This is an Open Source Offline Python editor, so when Colab cant work, Thonny will. There are no colab tools, just a great and simple offline editor and runtime. Used for years in learning environments. While still not for the pro user, it is great for smaller tasks and inexperienced users to to work with.

IDLE

IDLE is the IDE provided by the Python project. It is simple with few options, but it's well thought out. What options it does have are well considered and provide a learner with plenty of power. It's easy to setup and well supported.

Visual Studio Code

A text editor, but so much more besides. Fantastic fror HTML, PHP, and other scripted languages. Created by Microsoft and now open source, I hate to say it but I love this program and use it often for web dev and webapps.

Netbeans IDE

Pro grade Integrated Development Environment. This is a great tool for Java, C++, Javascript, HTML5 and more besides. I lived within this program at uni and still have an attachment to it.

Eclipse IDE

Another great IDE. As default it is designed for Java development, but it can easily be configured for most languages. I have used this for Android development. Again, a great open source tool.