If you mean the leafy greens kind of salad, I'm pretty variable in that I don't have one specific favorite, and prefer to mix things up (bad pun intended).
Honey mustard, usually homemade if I have time and freedom to make it.
Russian and/or Catalina are pretty nice when used sparingly, particularly if there's egg in the salad.
Vinaigrettes are great when I have access to antacids lol. Love the taste, but the heartburn can be a barrier.
Caesar salads need caesar dressing.
And, in a pinch, some lemon juice, salt, pepper and a bit of olive oil will get the job done.
For other salads, like potato salad, I do blends as well usually. But it's going to be blends of Duke's, Hellman's and miracle whip. None of them are perfect by themselves for every combination of ingredients, so it comes down to tweaking each batch until it's right. But usually it'll start with a 2:1 of one of the two mayo brands to miracle whip. Sometimes it's all three in equal measures to start. Rarely it'll be the two mayos only, or miracle whip with either small amounts or none of the others.
That last is typically only going to be a specific egg salad that has no pickle relish, so it needs the bump of sweetness and acidity MW brings to the table that gets muddied with mayo added too.
It's all about creaminess, flavor balance, and the palates of who will be eating.
Olive oil, balsamic vinegar, the not smooth kind of mustard, honey or syrup, onion, salt and pepper.
Or mostly the same but swap mustard for chilli paste (gochujang or samba olek) and the olive oil for toasted sesame oil, maybe also swap to different vinegar but balsamic still works.