According to Bangkok Post, there will be no more Test and Go Thailand program from the 1st of May and onwards for vaccinated travellers. The insurance requirement will be 10 000 USD, and there will be some self-testing with Atk.

Under the proposed entry scheme, travellers would still require to enter their vaccination information and health insurance data into the Thailand Pass system to attain entry. Nonetheless, guests will be free to explore Thailand upon arrival. 

Children under 12 years of age will be exempt from these restrictions.

 These changes will not be 100% ‘official’ until published in the Royal Gazette.

The Test & Go process for foreign arrivals will be terminated at the end of the month and vaccinated travellers will require only self-antigen tests for Covid-19 from May 1, to stimulate tourism and the economy, Prime Minister Prayut Chan-o-cha said on Friday

Also, expect that masks will still be required to be worn. But anyway, it is a considerable relaxation in the system.

Bangkok Post writes(28th of April) that the Thai Pass will be gone from June the 1st and probably replaced by writing relavant information on The TM 6 form.

For unvaccinated, there will still be a PCR test required before departure. And some quarantine. Test and Go Thailand is gone but follow updates on Colours of Thailand or read more about it in Bangkok Post.