This repo contains a Hashcat mask definition for generating a full list of more-or-less all possible valid mobile numbers in Thailand.
The prefix code data used was based on the current (Aug 2022) Wikipedia article.
The generated list (~280,000,000 candidates) is in no way guaranteed to be either complete or accurate. Use for hobby purposes only!
Assuming a working hashcat in your path (see forums for M1 quirks and workarounds), just type make. The generated file is about ~2.9 GB large, which prevents uploading to GH on the free tier, since it exceeds the current 2 GB limit.