I have a different reason for not thinking about mayo next year: I'm sensitive to eggs,
I've been eating it anyway as well as other things, and I have to stop: joint pain, fatigue, acid reflux, blah blah....
Anyway, my point is...personally I prefer onion dip with *only* sour cream. However ranch dip is really good with combos of sour cream/mayo/yogurt/milk or heavy cream.
I make my own onion dip with sour cream (my favorite is Daisy), dried onion flakes, granulated onion, and Worcestershire sauce. Yum!