Okay, looks like I can upload now.
Here is a photo of one of the tomato plants with what Looks like some kind of wilt, maybe bacterial wilt?
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Plant looks too big for wilt. Might be it's grown too much on top for its roots to support.
Wait..you say it's happening to all your indoor seedlings and young plants? Oh dear. The rest of that tomato plant looks properly perky. Think I'd pinch off the worrisome stalk and start hardening off the plants in bright light outdoors rather than in direct sun.
Neighbor farmer has had his tomatoes in the ground surrounded by 'wall of waters' since second week of February. As well as keeping the plant safe from frost, the wall of waters diffuses the direct sunlight so the plants don't scorch and have time to grow good root systems.(or so my farmer friend says)

Thanks, Dottie. I wish I could put them outside. I know they would be happier. This evening, the tomato is still alive and actually looks better, however several of the basils have died. I also have a few wilting angelonia and a couple of zinnias have died. I know I am going to kill everything because now I am paralyzed by fear - do I water, not water? What do I do to save these plants? I have separated the wilting ones from the healthy ones, but other than that, I don't have a clue as to what to do.

Oh gosh Wilson1 I feel you pain I live in Greensboro and have a ton of seedlings some of wich are doing the same thing it is definitly not need of water I read that my be poor air circulation and lack of sun(wich explains) I am about to give up the plants that are mostly afected are artichokes,zinnias,beans my tomatoes look good and the basil is not groing.

My earlier experiences with indoor seed starting resulted in much the same as described above. I was told it was too much watering from the top...need to water from the bottom, not allow plants to sit in the water, and/or mist fequently, which is what many nurseries do. So, I now mainly use winter sowing to avoid having to make decisions...lazy gardener I am for sure. This watering advice is not going to help this year, but try it in the future.

NCrescue, I have to say, that is the conclusion I am coming to. I am pretty nervous about trying winter sowing, but everyone who does it seems to swear by it. I am now thinking it is a watering problem. I had been watering only from the bottom, but when we had those 80 degree days I put the seedlings outside, they got dry and I gave them all big drinks. The problem started after that. So far only a few things have died - not the mass exodus I was dreading - and now I think it was human error :)
I need to come to one of the plant swaps to talk to people about the details of winter sowing.