Are you looking for just bare boards made (and you will hand assemble), or do you want to send them full design and get fully assembled boards back? I only have experience with the former, and no I haven’t found a place that will manufacture just a single board of a design. But, OSHPark does them in multiples of 3, so you could get 9 of one design and 3 of each other design. Yes you are getting more boards than you need, but after messing up one board you may be thankful to have a spare. (Or even if the first board is fine, you decide you want to make some modifications, you can do that (cut traces, run jumper wires, etc) to the spares.
Also, OSHPark can take the kicad PCB file directly if you are comfortable doing that. (Some people aren’t and will generate gerbers anyway. But you have a choice.) I think there are some other PCB prototyping services that also take the KiCad board file instead of gerbers.
Check out https://pcbshopper.com/ and enter in your board basic specs (you’ll need to do this 3 times, once for each of your designs). Then look through the list and choose the option that works for you. The quotes will show where the company is located, the minimum order quantity to reach your desired quantity, pricing three ways (total board price, price per board, and total order with shipping), and gives the expected lead time for the different shipping methods. No, PCBShopper doesn’t show all possible manufacturers, but all the ones that are listed on PCBShopper are friendly to the hobby maker (and cottage/small industry).