What cover crops to use on newly built swale - Zone 5

Do you have any "recipies" for seed mixes that one can use just after digging swales, to sow on berm and back cut? I'm in a cold temperate climate, zone 5, soil is sandy and the slobe faces south/soiuthwest (lots of sun). I assume these should be mostly legumes, aren't they? Lupin, clover? I want it to be as diverse as possible.

Clover, Lupine, vetch, plantain, anything you want.

Make sure to add fast sprouting stuff and stuff with good root structure as a nurse crop--buckwheat or any grain for your climate and planting time.

I am in zone 5 in northern New England with 3 swales we built in mid May of this year.

I am trying a couple of different things with my swales. I have a 224' swale I have planted buckwheat, diakon and other radishes, white and red clover, vetch, field peas, rye grass, sunflowers, summer and winter squash, comfrey, left over tomato plants, chives, garlic chives, watermelon, wheat seeds from the straw and a few other random spouting seeds I had. The radishes sprouted first. Everything else is just starting to sprout. I have no idea how well it will work and what I will harvest out of it.

I planted one 55' swale with annual and wild flower seeds from FEDCO. I have also put a bunch of flower seedlings, bulbs and comfery in it. My plan is to use it a a nursery and propagate stuff out of once the perennials are established. This is the list of wildflowers in seed mix I planted.

(Latin name, Common name, Plant type, Height, Color(s), Season)
Achillea millefolium, White Yarrow, P, 18-36", White, S
Aster novae angliae, New England Aster, A, 24-36", Purple, F
Centaurea cyanus, Cornflower, A, 24-48", Mixed, S
Cheiranthus allionii, Siberian Wallflower, P, 10-18", Orange, SP
Chrysanthemum maximum, Shasta Daisy, P, 16-24", White, S
Coreopsis lanceolata, Lance-Leaved Coreopsis, P, 18-36", Yellow, S-F
Delphinium ajacis, Rocket Larkspur, A, 12-36", White/Pink/Blue/Violet, S
Dianthus barbatus, Sweet William, P, 12-24", White/Pink/Red, S
Echinacea purpurea, Purple Coneflower, P, 24-36", Purple, S
Gaillardia pulchella, Gaillardia, A, 12-24", Yellow-Red, S
Gypsophila elegans, Annual Baby's Breath, A, 8-18", White, S
Liatris spicata, Gayfeather, P, 24-48", Purple S-F
Linaria maroccana, Spurred Snapdragon, A, 18-24", Pink/Yellow/Violet, SP-S
Linum grandiflorum rubrum, Scarlet Flax, A, 12-36", Scarlet ,S
Lupinus perennis, Lupine, P, 12-36", Blue, SP-S
Oenothera lamarckiana, Evening Primrose, P, 24-60", Yellow, S
Papaver rhoeas, Corn Poppy, A, 12-30", White/Pink/Red, S
Rudbeckia hirta, Black-Eyed Susan A/B/P, 12-36", Yellow, S-F
Silene armeria, Catchfly, A/B, 16-22", Pink, S

I also added a bunch of cosmos and zinnias because I like them.

The 50' swale is full of cooking herbs. rosemarys, sages, thymes, loveage, chamomile, catmint, oregano, basils, parsley, lavender, fever few, lemon grass, and chives. Again the perennials will be propagated an planted elsewhere.

My basic cover crop mix is:
winter rye (first to sprout)
sweet clover
sainfoin
hairy vetch
alfalfa
chicory (deep tap root to break up dense sub-soil)
buckwheat

Lately I have been adding pinto beans, bush green beans, peas, and some squash.

Many thanks for your replies, this gives me some ideas to work with.

Onion family
Mint/thyme family
Dutch Clover
Dill/Cilantro
Daikon Radish (all season)
Wine Cap Mushroom if I have mulch

I know that some people like something from the grass family, I dont, but if I was going to use one it would be winterrye or corn