- Flour
- Sugar
- Eggs
- Butter or Oil
- Water
- Baking Soda
- Baking Powder
Cake. All cakes and lots of other baked goods have these same ingredients but not all cakes taste alike.
You do not have to be hungry to eat cake, you will rarely say but I had cake yesterday and I just don't feel like eating some cake today. It's cake!
Use a lot of butter and you get pound cake. Whip the eggs and you get sponge cake. Add cocoa and get chocolate cake. Eschew the use of flour and get cheese cake. Use yeast and get coffee cake. Change the ratio of ingredients slightly and cook it on a griddle to get pancakes. Change it again and bake it in the oven on a cookie sheet and get biscuits. Then there's bread, crackers, scones, cookies, pie crust, pastries, ad infinitum ...
It's the same with D&D and most other RPG's, okay? Same ingredients, so as you're mixing them up you may think you're fixing the same old thing. You're not. That batter may look like every other batch of batter you've ever seen, but it's your special touch and a handful of nuts, or cinnamon, or fresh slices of apples, or vanilla extract, that make it something different.
Don't let the fact your campaign isn't completely world-changing in scope and depth stifle your creativity. Create a campaign in your own vision.