I only have a pastic shhet form with strategic holes to fill out for date, pay to, amount, signature.

If the check has to go in the mail, you could always do online bill pay through your bank.
I know this isn’t exactly what you were asking, but my wedding venue only takes checks and I have been able to successfully pay them to the tune of $30,000 this way, sending a couple of thousand dollars per month.

I think there was a program called Talking Checkbook or something that would allow you to print checks, but this was back in 2005 or so. I don’t know if it is still around.

How often are you writing checks? You could always try check paper and check printing software but I don’t know how accessible the softwares are and it can be a pain to make your own check… you can probably also use a check guide like mentioned or even ask someone else to write the check and then sign your name with a signature guide or even make a signature stamp (sign once, never again lol). Most banks do offer e checks these days though which might be your best option- and if you need to write a check to pay rent etc I’ve heard of landlords taking electronic payment as a reasonable accommodation. Idk if this helps but hope something might be of use to you.

Most banks have apps with varying degrees of accessibility. There are plastic cover templates to hand write checks.

just waiting for someone to ask about accessible fax machines now and that'll be my day done.

I’ve never had to write a cheque.

This might be a cultural difference though - I occasionally receive one from a company but cannot think of a situation where I would need to write my own

There are some check books that have a tactile line. I don’t know if they would be valid for any bank. There are plastic overlays that can help people aline the check to fill it out.

I use the metal pre made fillers. If the writing is hard, you can have your bank teller fill it for you.

No not that i know of.