Skills
Design Experience
Features that I have worked extensively on through ideation, iteration, and polish
Systems
Progression
Rewards
Player Gear
Social Gameplay
Crafting
Player Skills
Game Economy
Character Creation
Matchmaking
Engines & Languages
Engines and languages I have experience in through professional work, education, and game jams.
Unity
Unreal
C#
C++
VBA
Fortran
Tools
Although last in the list, I believe these tools to be just as integral for the game designer as the others listed above.