Games

Downpour

• Authoring
• Games
• Gamification

Fun mobile app (Android, iOS) with which you can make quirky games.

List of Game Development Tools

• Games

Everything from Twine to Unity... tools to make games.

Godot Engine

• Coding
• Games

Free, open source games development environment. One day, I'll get round to having a go with Godot.

Twine

• Authoring
• Games
• Interactive Narrative
• Writing

Write interactive narrative fiction (the online version). Create your own adventure game!

GDevelop

• Game
• Games

Create 2D games without coding. 

PyGameZero

• Games
• Python

Successor to Pygame, PyGameZero is a python-based game engine that is fun to use, easy and powerful.

Study Crafter

• Game
• Games
• Interactive Narrative

An amazing tool to create interactive games with a flow-coding interface, but equally could be used to make training materials. The primary use for this tool is to collect research data about what choices people made.

Free.

The Museum of Screens

• Game
• Games

Interesting "walk" through internet time

Great List of Games

• Game
• Games

53 best browser games you can play for free.