Salsa is a good option. Pickling is too, or chutneys in the same vein.

Nobody here has recommended fried green tomatoes yet? That's a southern staple

Pickled green tomatoes are amazing. My family makes them every fall.

Salsa!

Chow. Try it with some curry paste added as well. Yum.

Chowchow! Its my go to for green tomatoes.

Eat! They are so tasty

HealthyCanning is an excellent resource for safe canning recipes. They have several green tomato recipes here: https://www.healthycanning.com/tag/green-tomatoes

Given these are cherry tomatoes, I'd especially recommend this recipe: https://www.healthycanning.com/pickled-green-tomatoes

I've also found that salsa freezes surprisingly well in wide mouth mason jars.

Finally, if you let them sit out, many (most? all?) of your green tomatoes will eventually turn red.

Fry them

Green ketchup

I preserve them in oil. It takes a bit of time but so worth it! I just use the bigger ones for this and make salsa or enchilada sauce with the small ones.

Green tomatoes in oil

Edit: you could just cut the small ones in half and do this. Hmmm, might try that next year.

Marmalade!

I cook them with peppers, other veg, and ripe tomatoes (or sometimes tomato paste). Makes an excellent chunky veggie sauce.

My dad makes chutney with the end of the crop.

If you have 13 kilos you should probably freeze some of it. I would probably roast them first. That will make them a bit less sour and they will contain less water thus it takes less space in the freezer. Oh and discard the super tiny ones, they will just make the rest of them taste bed.

Oh and you can use them in any soup or sauce and you won't be able to tell they were frozen.

Sell at a high markup to vegans.

you can fry them with oil/butter, onion, garlic, and salt on a pan, they're good

Green chili? Tomatillo salsa. Otherwise probably do your best to preserve the rest.