I grow rhubarb, asparagus, garlic and the bunching onions already but I may have to add a few more.
I am a big fan of perennial veggies and herbs.
This year I added several more perennial herbs that are good to add to salads.
Some you can use more than others in a salad and some just a couple of leaves are sufficent.
Herbs like the Pineapple Sage, Verbena, Borage, etc. are good to add to cold drinks for flavor or aesthetics.
I call this area of my herb garden my Salad Garden.
Burnet, Sorrel, Good King Henry, Bloody Dock, Red Valerian, Costmary and I am probably forgetting something here.
I plant Lemon Verbena and Pineapple Sage in this garden as well but they are not perennial in my zone but are in zones 8-10 or 11 so I plant them each year and they are well worth it.
I also grow Borage and Nasturtiums in this area too but they are not perennials, although Borage readily reseeds itself each year.
Lovage is in this garden as well due to space requirements but it may taste alright in salad, haven't tried it yet but I know Reinbeau loves it in potato salad so technically I guess its okay for it to be in my
Salad Garden.
I also have Fennel and Dill for salads but they live next door in the Cooking Garden.
There are probably alot of others but I only grow what I like to eat instead of for the sake of growing something so I am probably missing alot of others that you may find in a search.