I actively enjoy encoding knowledge planning models, usually in PDDL or PDDL+.
Some of the models I engineered have been used in International Competitions, while others have been used for testing the exploitability of planning in some real-world applications. I also modified well-known benchmark models to test the robustness of state-of-the-art domain-independent planning engines.
All the models can be found in a bitbucket repository I specifically designed, https://bitbucket.org/maurovallati/planning-knowledge-models
Feel free to the models for your research, or just to play a bit with planning engines.