These are the 40 inventive principles that have been used in hundreds of thousands of patents. You can use them via TRIZ Contradiction Analysis or standalone, as stimuli to prod your thinking forward.
(hold mouse over each word for a description – not actually linking to separate pages)
1. Segmentation
2. Extraction
3. Local Quality
4. Asymmetry
5. Combination
6. Universality
7. Nesting
8. Counterweight
9. Prior Counteraction
10. Prior Action
11. Cushion in Advance
12. Equipotentiality
13. Inversion
14. Spheroidality
15. Dynamicity
16. Partial, overdone or excessive action
17. Moving to a new dimension
18. Mechanical vibration
19. Periodic action
20. Continuity of useful action
21. Rushing through
22. Convert harm into benefit
23. Feedback
24. Mediator
25. Self-service
26. Copying
27. Inexpensive short life
28. Replacement of a mechanical system
29. Use pneumatic or hydraulic systems
30. Flexible film or thin membranes
31. Use of porous materials
32. Changing the colour
33. Homogeneity
34. Rejecting and regenerating parts
35. Transforming physical or chemical states
36. Phase transition
37. Thermal expansion
38. Use strong oxidisers
39. Inert environment
40. Composite materials