I don't know if this fits the your idea of a potluck but it's easy and yummy to bring:
cauliflower and broccoli salad
1-2 heads of each (really as much as you want)
mayo (light if you want)
dash of wht vinegar
sunflower seeds (no shell/salt free)
dash of wht sugar
cut heads into bite size pieces, add the rest of ingredients into large bowl/serving container, mix together the night before and let sit in the fridge overnight with a lid on, next day stir and serve
I also think a slow cooker is a must in any home, sooo quick and easy