mayonnaise of course
or wrapped in bacon or better: Parma ham, or any other healthy ham from Italy or France.
You can also do it as the Danes from the Island of Bornholm: on top of a smoked herring fillet ... ah but wait, it's not boiled in this case.
You can also cut your eggs in pieces, add pieces of fresh tomatoes, spring onions and avocados, on a bed of rucola salad with basil pesto and Parmesan cheese. I don't know, there are zillions of ways to treat your eggs