I thought ALL egg salad had mustard in it? But now that I'm thinking about it, I've only had my mom's egg salad but she's always put mustard in it. I guess I didn't know a non-mustard variety existed! Hmm, the things you learn!
most deviled egg recipes call for vinegar, mustard, and salad dressing or mayonnaise. my grandmother always uses dill pickle juice instead of vinegar. gives it a really great taste. i'm sure you could do egg salad the same way.