I have used these for my veggy garden transplants for a couple years now. They work great.
https://www.johnnyseeds.com/tools-supplies/seed-starting-supplies/soil-blocking/hand-held-4-soil-blocker-7862.html?cgid=soil-block-makers#start=1
They make a few different sizes.
Also really great thread. To say you pay attention to detail would be an understatement to say the least lol