Mighty Monsters - Mighty Monsters offers a fantastic combination of Adventure-based Puzzles and RPG elements and takes you to a wonderfully colorful world filled with a number of different monsters and creatures.
OpenTTD - An open-source clone of the classic game ...
Monster Galaxy: The Zodiac Islands - Monster Galaxy: The Zodiac Islands is enticing new Adventure, Puzzle and RPG video game by the popular Gaia Interactive Inc.
Simutrans - Simutrans is an open-source transport simulator.
Pocket Frogs - Pocket Frogs is an Addictive, Hunter, Breeding, Training, and Single-player Simulation developed and published by NimbleBit LLC.
Transport Tycoon Deluxe - Transport Tycoon Deluxe is a Business Simulation developed by Chris Sawyer and published by MicroProse.