Many people have discovered the joy of wildflowers that re-seed or spread, generally popping up randomly in your yard. I'm here to tell you that if you loosen the reins on your veggie patch you can have the same kind of fun. Three years ago I planted a loose-leaf lettuce mix. Every year since then I've had lettuce without planting it. I just let my favorites go to seed.
Loose leaf lettuce is great because you can snap off a mass of leaves and they'll just grow new ones as long as you leave the central crown. The flowers are kinda cute too. They have yellow or white daisy-like panicles of flowers. Although they do look a bit weedy when the fluffy mass of seeds appear.
Speaking of weeds, you'll need a good amount of open ground for this to work, so you'll have to tolerate some amount of weeds on your veggie beds. The lettuce always ends up in different places (occasionally there's a plant in the lawn) but crop rotation is a good thing anyway.
I often find that the lettuces are up as early as when the crocus blooms, so by the time of daffodils you might have a good salad going, especially if you do the same thing with radishes.