More pollinators mean a bigger crop for your efforts.
Try plants like chamomile, cosmos, and coreopsis; herbs that flower are all favorites of pollinators that prefer flowers with flat surfaces or else ones with hidden nectar spurs like larkspur and snapdragons, which bumblebees prefer.
Remember that pesticides, even natural ones, will discourage pollinators and should be used sparingly if at all in the garden.
If you cover your crops to shield them from pests, you will need to uncover them for part of the day to allow the pollinators access to the flowers in order to get a good crop.