Many decades ago I invented The Grocery Planner...a lightweight calculator-type of alphabet printer which attached to your fridge with back magnets.
The 4 main buttons we're Milk, Bread, Butter, Eggs...for the rest of your groceries you would just type in the name...like...bananas
Then, you'd simply hit print and your grocery list would print out. Just tear and go.
I never saw the idea through, but often wondered if it could have been a big seller.