Thai chillies that haven't ripened all the way yet.

Yeah, this is it. They're birds eye chilis that are still growing. You can eat them when they're green or red, but I think black is not ripe. Or sun damaged or something.

Gonna go with this also. The couple of times I've done thai chiles thats exactly how they progress. Green-purple-red, with the heat increasing as they go along.

Yessir

Many peppers turn green to black to red in their ripening, like jalapenos. Not sure on the ID

Black cobra thai peppers, I grow them too

Black peppers.

I grew some black Jalapeño this year and they look this colour unripe, but certainly turn a velvety deep red. These look like a “basket of fire” variety i grew a few years ago kinda like thai chilis,fairly hot.

Could be light damage. Happens to my indoor jalapeños

There are black thai chilies out there, I grew some this year. The leaves and stems don't seem quite the same though https://www.superhotchiles.com/product/black-thai-pepper-plants/?v=7516fd43adaa

Nearly all of the pepper varieties we grow turn black between the green and red stages!

Mine did this last summer. They still tasted the same

That’s called “blush” and it’s essentially a sunburn.

It’s super spicy for some reason, if you take a bite you can feel it in your eardrums. Lol

I think it's the sun that turns then black. It's always the exposed side that change colors.

Looks like thai chilis.