I'm no expert, but...

The peas, unfortunately, look normal. White streaks on the leaves is perfectly normal according to variety (it doesn't indicate anything good or bad normally), and the dying off at the bottom looks like the plant has just had too much heat and is giving up the ghost, like peas do. They're a cool weather crop, so you may want to consider replanting in the fall.

Your cilantro, I would guess has sunscald - does it get full sun? It likes shade during the hottest part of the day.

I have no idea about the tomato, although it does look rough.

I'm sure someone with more experience will pipe in if I'm off base.

I think your tomatoe leaves have a case of blight. If you are overhead watering, don't. If you must overhead water, do it in the morning so the leaves will have a chance to dry off quickly. Also, try planting blight resistant varieties, there are many to choose from. Your peas leaves with the striping are just fine.

Thanks for the responses. These make sense, as I am overhead watering, which I'll stop doing; and we've had a very wet, cold season until about Friday when it suddenly became scorching hot.

Such a newbie, I didn't know the sugar snap peas are a cold season crop! I put them in really late, in that case!! They just started producing. Ah well.

Is there anything I can do with the cilantro or tomato plants? Could the blight move to other plants? Near it, I have basil, bell pepper and the already mentioned cilantro. It's at the very end of my 20' garden, but depending on how it could travel...

Early blight is a very common fungal infection that makes rings like a bulls eye on the leaves with dark rings, darker rings, and yellow spreading out from the infection spots. If this is what you have, it will spread quickly and has the potential to kill the plant or severely stunt production. It is however treatable, and even organically treatable. The first step is, if you only have a few infected leaves on the plant and the plant can live without those, the best thing is to remove all infected leaves. At least remove severely infected leaves because they're as good as dead anyway. Make sure to remove all fallen leaves from the garden and put them in the trash, NOT the compost. Don't handle healthy plants after handling infected plants without washing your hands thoroughly with soap. Next what works for me is to treat with a dilute vinegar spray. Mix 3 tbsp apple cider vinegar with one gallon of water and 1/2 tsp cooking oil. Spray this lightly on the leaves and on the soil around the plant. Do only a light misting and don't pour it on, too much vinegar will harm the plant but just a little will only harm the fungus. Do this twice a week for two weeks. This levels the playing field by killing all fungi present. Then begin a cornmeal and compost treatment to encourage only the beneficial fungi to grow back. You can brew a tea of cornmeal by putting one cup of regular grocery store cornmeal into an old pair of nylons, then place the nylons like a tea bag into your watering can and let this steep for at least 24 hours. Spray this on all your plants, it's only helpful and not hurtful so don't worry about doing it too often or too heavily. You can also spray with compost tea (make a "tea" in this same way with the nylons except fill them with compost instead of the cornmeal) and spray this on to boost healthy fungi populations. You can also sprinkle cornmeal on the ground around your plants for a natural fertilizer and fungal protector (but sprinkle some soil on top to hide it from the ants). The key here is to give the healthy fungi a fighting chance against the harmful ones. If you encourage a good population of helpful organisms in your garden, those organisms will kill off the harmful ones and you will have healthy plants.

The tomato may have a blight, but all the other photos look like it might be a manganese deficiency.

Go to the photo site below and chicken out photos labeled DEF11 and DEF13. It looks awfully close, doesn't it?

You don't say where you are. Are you in an area of high rainfall and/or acidic soil? Normally, there is enough manganese in animal manure to avoid deficiencies, so if you are amending the soil with those manures, it SHOULDN'T be a manganese deficiency, but something else. Green manures will not add it.

Manganese is a trace mineral, so you don't need much. Below is a site for information on dealing with it.

Here is a link that might be useful: Manganese deficiencies

This is all new really high quality soil, so I'm not sure that's it. Composted manure was added along with soil conditioner and I've been using an organic fertilizer once a long as well.

I'm in Maryland. It's been a VERY wet, colder than normal season, until Friday when it shot up to 95 - 100 for several days.