OpenTTD - An open-source clone of the classic game ...
Thunkable - Powerful but easy to use, drag-and-drop mobile app builder.
Transport Fever - Transport Fever is an Adventure-based, Management, Strategy, Economy, Sandbox, City-Building and Single-player video game developed by Urban Games and published by Gambitious Digital Entertainment.
MIT App Inventor - App Inventor is a cloud-based tool, which means you can create apps for phones or tablets right in your web browser.
Railroad Tycoon - Railroad Tycoon is a very first installment in the series of Railroad Tycoon that was released in 1990 developed by MPS Labs and published by MicroProse.
Bubble.io - Building tech is slow and expensive. Bubble is the most powerful no-code platform for creating digital products.