Capers and Cavier
Yums.
Yes. Also, onion and garlic powders.
Must try the ground bacon idea. May have to cook up extra slices of bacon, just in case …
My deviled eggs are very simple - what I would consider classic for where I live. Sweet pickle relish, minced onion, mustard, mayo, salt and pepper. I garnish each with a thin slice of a pimiento olive.
When I’m in a hurry I’ve discovered that a dollop of thousand island salad dressing will do the trick.
Daughter makes what she calls Greek-style deviled eggs and they are to die for.
Here’s another trick I use for taking them to a cooperative dinner: I slice them crosswise rather than lengthwise. Mince it up very fine and add to yolks so as not to waste food, Mom says.
Then on the pointed end I slice a little off so they will stand on their unsliced sides. This way you can pack many of them in a carrier and they aren’t so apt to slide around and goop their filling all over each other. That’s just plain yucky.
I think of them as Summer food and seldom make them in the Winter.
I once added some mango chutney chopped finely to the standard filling. It was good.
I don’t want to throw this out as a fact, but I was always told to put vinegar in the boil water so that if an egg were to crack while boiling, the egg white would solidify and seal the crack before the white could leak out into the water. I have seen evidence of this working but I have also never cooked eggs without the vinegar to test Mom’s advice.
I made deviled eggs for our fantasy draft and added crumbled bacon and green chiles to the mix. Topped each one with a slice of pickled (towel-dried) jalapeno. Everyone raved about them.
This is it! I use Duke’s mayo only though. Cider vinegar, NO MUSTARD! A touch of salt. Then I pipe into the egg whites so they are pretty enough to not need paprika. People fight over my deviled eggs if I take them to a party. No one believe they are so simple, but I can’t believe how many people screw them up by putting so much junk in them. 
These probably don’t count as proper deviled eggs, but are similar enough to mention:
First you buy or make filet americain préparé. Despite the name, it’s a Dutch and Belgian thing and all butchers/delis have their own recipes. Basically, it is steak tartare with finely ground pickled silverskin onions and/or gherkins and/or capers, salt, pepper, mayo, tomato paste and pepper sauce and/or mustard.
Mix the préparé with the yolks and additional pepper sauce and fill the egg halves. Delicious.