Mayonnaise? Fucking delicious. Easily the best condiment. Goes great on nearly everything.
You know those combination sauces that Heinz released a while back that everyone dunked on, like "mayochup" and "mayocue"? Also delicious. Mayo mixed with ketchup is the best sauce for fries, and mayo mixed with barbecue is great on sandwiches.
Every downvote on this post increases my self-esteem.
if you're able to get it, perinnaise is exquisite - it will probably be in a british portion of the grocery store despite it being a sauce from portugal i guess