@Andrew *********
ASSUMING everything returns like it was Pre-COVID-19 (including the borders reopening, no Thai Pass, no health insurance, etc...).
1. A person can enter Thailand TWICE by land in a calendar year on a visa exempt. A person will be granted ONE 30 day extension of stay based on tourism, which can be extended ONCE by another 30 days.
2. A person can get "unlimited" tourist visas at neighboring Thai consulates (the Thai consulate in Vientiane, the Thai Consulate in KL, etc), until the Thai consulate says "no", and tells you to get the correct visa for your stay. When one consulate says "no", try another.
3. A person can get "unlimited" visa exempts by air. A person will be granted ONE 30 day extension of stay based on tourism. It is "unlimited" until passport control says you're abusing the system and rejects you on entry.
AS OF RIGHT NOW (During COVID-19), only Cambodia is open for air-based border bounces. I have not heard of any reports of how this is actually implemented, or anyone who successfully did such a bounce.