Copernicus Open Access Hub online tool.

Looking at our planet and its environment For the ultimate benefit of all European citizens... The Open Access Hub provides complete, free and open access to Sentinel-1, Sentinel-2, Sentinel-3 and Sentinel-5P user products... 
Copernicus builds on a constellation of satellites making millions an impressive number of daily observations, as well as on a global network of thousands of land-, air- and marine-based sensors to create the most detailed pictures of Earth. The technological evolution, especially in terms of availability and accessibility, has made Copernicus the largest space data provider in the world, currently producing 12 terabytes per day. 
The vast majority of data and information delivered by the Copernicus Space infrastructure and the Copernicus services are made available and accessible to any citizen and any organization around the world on a free, full and open access basis. You can access Copernicus Data and Information Services through the DIAS or the Conventional Data Hubs...
See this online tool scihub.copernicus.eu with data and maps from satellites...

The home build tool with Planner5d.

This online tool lets you build into 3D space.
The development team comes with this intro:
Create your dream home An advanced and easy-to-use 2D/3D home design tool. Join a community of 47 217 259 amateur designers.
The online tool can be found at this website.
This is a screenshot with this tool from the website:

Shadertoy: The sin math function - 001.

Another example with shadertoy online tool.
The example come with all comments to understand how the sine function is show on shadertoy website.

MakeHuman: Nightly builds of (most) plugins.

At 11/18/2019 the MakeHuman team development comes with many plugins for MakeHuman software: These are plugins related to MakeHuman. The MakeHuman side plugins are installed by placing the directory (for example "9_export_mhx2") in the "plugins" directory where you unzipped or installed MakeHuman. On linux this is usually /usr/share/makehuman/plugins. The Blender side plugins are installed in Blender, in the addons part of the user preferences.
See the official website.

Lutris the Open Source gaming platform for any Linux distro.

Lutris is an Open Source gaming platform for Linux. It installs and launches games so you can start playing without the hassle of setting up your games. Get your games from GOG, Steam, Battle.net, Origin, Uplay and many other sources running on any Linux powered gaming machine.
You need to create an account and you can run many games on Linux and multiple platforms, see the official website with games.
If you want to install it with your Linux distro the take a look at the official webpage.
I used the installation process on Fedora 31 with DNF tool:

[root@desk mythcat]# sudo dnf install lutris
Last metadata expiration check: 0:06:35 ago on Wed 04 Dec 2019 07:15:23 PM EET.
Dependencies resolved.
======================================================================================
 Package                    Arch       Version                      Repository   Size
======================================================================================
Installing:
 lutris                     x86_64     0.5.3-1.fc31                 fedora      2.0 M
...
Total download size: 129 M
Installed size: 708 M
Is this ok [y/N]: y
...
  llvm-libs-9.0.0-1.fc31.i686           ncurses-libs-6.1-12.20190803.fc31.i686       
  python3-evdev-1.1.2-4.fc31.x86_64     unixODBC-2.3.7-5.fc31.x86_64                 
  vulkan-loader-1.1.114.0-1.fc31.i686  

Complete!

Inkscape : Top 5 Finalists.

The About Screen Contest for Inkscape is a conquest for Inkscape contributions to the artistic presentation.
The Final Voting: Mon., December 2, 2019 – Sun., December 15, 2019 and the winners will be announced: Tues., December 17, 2019
The community chooses the top 5 Finalists in version 1.0 About Screen Contest.
Congratulations to our Top 5 Finalists!

1. 'Island of Creativity' by Bayu Rizaldhan Rayes
2. 'Graphic Design' by Bożena Augustyn
3. 'Migrate to Freedom' by Bayu Aji
4. 'How to Fold a Memory' by Dismecha
5. 'Inkscape 1.0 About Screen' by Rania Amina

See the final result on the official webpage.