OK, so as of 4pm today visa exempt entry stamps switched to a ผ.60 stamp meaning you get 60 days on entry and can extend once for 30 days at a local immigration office.
These are the countries eligible.
TLDR : Answer Summary
As of July 15, 2024, Thailand has introduced a new visa exempt entry stamp that grants travelers from eligible countries a 60-day stay upon entry, which can be extended once for an additional 30 days at a local immigration office. There are queries regarding the application of the new stamp, particularly for those entering through land borders, and concerns about the status of this change, notably its publication in the Thai Royal Gazette and its implications for different nationalities and visa types.