Several things, looks like.

Squirrels and chipmunks ignore rabbit fences.

There is something else eating the lvs on tomatillo, earwigs and older slug evidence.

Stems on 'Brandywine' look normal from here but just go ahead and pull that.

Dan

Thanks for the response, Dan. I just read a post that suggests calling the County Agent, which I did, and he said it sounded like cutworms and I need 2" tall plastic or cardboard collars around all the plant stems. I guess I will be starting over with these squares now.

Looks exactly like what's decimating my seedlings. I had a massive infestation of earwigs. The only thing I found that works for them without destroying the other good bugs is direct assault. (Trust me, I mean assault. I was so mad when they destroyed my plants.)

I got a jar/cup of soapy water and a pair of tweezers and went out about an hour or two after dark and plucked them right off the plant/planter/soil and dunked them right into the soapy water. Yes, I realize that they're helpful in the fact that they eat other bad bugs, but a big infestation is just not good at all as they're omnivorous.

I would suggest going out with a flashlight, get all the ones you can find, then come back in a couple hours and do it again. I had to do it over a span of three nights, but now it looks like they're finally retreating.

It might be cutworm, hollan, hard to tell at that resolution. Of course you should be able to find them in the soil still. If you cannot find them, it is something else.

Dan

I would think ( and I could be wrong) but from past experience with cutworms....if it was indeed cutworm damage, that not as much of the stump of the stem would be above ground.
Does that make sense?
They cut off at the soil line or a little below...not up the stem like that....atleast from my experience.

Earwigs are aweful here too...I'd suspect the slug and earwig diagnosis.
Last year I had slugs knock my little seedlings right down to the ground......This year I cut paper towel tubes in quarters and put those around the stems of my seedlings.
I did this to prevent not only their damage...but, to try and help with squash vine boarers.

I would look at it from the bright side.....you get to plant some new things with a little more perspective now! :O)

Yes, the only positive is that I have learned something. Thank you all for your diagnosis. The paper towel tube is a great idea, and something I can cut and then tape around my remaining plants.

Some cutworms are above soil level, but IME the ones that have gotten me are at soil level like SC notes, and the 'cuts' are not as clean. But again with that resolution can't tell & they will still be in soil to verify. I just set out some containers of vegetable oil for my earwigs.

Dan

I would vote for cutworms. Dig around the damaged stems in the top inch or two to find the little devil(s).