We found a recipe for pickled green tomatoes we're trying out. Let you know how it goes.
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.