What is the insurance requirement for a Non-OA visa application in Thailand?

Check the Thai embassey website.

The insurance company must complete forms, and forms submitted with OA application.

There is a list of acceptable insurance providers on the Thai immigration website, those companies have policies that match OA Visa and can provide the forms easily.

Option1: get all your medical insurance with Thai approved provider.

Option2: get minimal insurance with a Thai approved provider just for the OA application, and a larger insurance policy with any provider you choose.

Motor bikes and cars:

If you have an accident and don't have a Thai accepted driver's licence for the vehicle then your medical insurance will be denied. Don't drive without a proper licence. Many do drive, and many have accidents, and their whole vacation is ruined. Best to avoid motorbikes. Tuktuks are cheap.

Travel insurance will not be accepted you need a proper health insurance with 3 million baht equivalent coverage

For the OA you apply from your home country and use your home country insurance. You meet the financial requirements using money in your home country bank accounts. The OA allows you stay in Thailand for 1-2 years. If you then choose to extend your OA inside Thailand then you must have Thai insurance.

I had an OA for 6 years.

Here is the official list.

you need 100K USD or 3million baht coverage for a year

If you don't use one of the approved thai companies for the insurance

your insurance company has to fill out and sign/stamp the form on this page