What are the requirements and good programs for obtaining a non-immigrant O visa for teaching in Thailand?

Find another avenue of work. Most likely in all probability will not happen with teaching. Plan accordingly

If you do not have a university degree you can not legally teach in Thailand, no matter what courses you might take thinking you can. The degree also must be certified as being real, so you can not buy a fake on KhaoSan road anymore to meet that requirement.

Another thing to know is to be a legal teacher, you need to

Might not want to advertise the fact you'll be working without the correct visa. If you're looking for a teaching role you need a degree as a minimum with TEFL or similar qualifications. Depending on what country you're from there are loads of options online and in UK definitely tons available face to face to ensure you are a competent and confident teacher. If you're serious about teaching and not a qualified teacher, I'd suggest getting as much experience and training before you actually start to attempt children or adults. Well paid jobs are given if you're suitably qualified at a high level in international schools 🙏🏽