Pressure Soft-Body Physics - Simulates a water-balloon like shape that can have 3+ faces using an advanced method.

Dynamic Fractures - Making a single object break into smaller objects dynamically.

Advanced Leveling - Shows how to use a mathematical slope function to calculate level requirements.

Zac's Cartographer - Teaches placing and deleting tiles with GML and can be used to populate maps with geographic features.

Game Maker 8 is required to open most of the examples, some come with executables to run them without it.
It is possible to open them with older versions of GM by using a program called Lateral GM