What's your favorite unexpected strikes or combinations that land and do damage? For me. Its the spinning back kick
When I was competing I would throw a right jab, left uppercut, and right roundhouse in as close to each other as possible. I almost always scored.
Spinning back kick is not really a thai boxing move. Unless you land it sweet it's going to leave you very off balance, and as we know, if you are off balance you lose points
Is the spinning back kick not known as "the crocodiles lashes it's tail" or somesuch in Thai? Maybe more a Muay Boran move?
Reverse roundhouse kick - yes muay boran, usually such moves are only seen as a showboat move rather than a scoring move
The spinning backfist, I like to throw this after I've slipped an opponents jab, sometimes I'll follow this up with a mid kick.
Teep to the liver when the opponent enters. Enter with a weave towards my lead foot and throw a long cross/overhand. More teep. Roundhouse to the inside of the lead knee when the opponent commits to advancing. Lead leg high roundhouse. Axe kick. Slip+jab versus a jab on a guy with matched feet. (orthodox for me) J-step and jab over the shoulder versus a jab on a guy with reversed feet. (southpaw for me) Headkicks against the direction of travel when an opponent circles, especially out of a corner. Headkicks or long straight punches during clinch breaks. And I'll throw spinning hooks and cartwheel spinning hooks for the showboat factor sometimes. They catch people entering from time to time and if they do land... it's bad. (EDIT: Spinning hook kicks, for anyone who was unsure.) But note, I'm a sambist and sometimes boxer who likes some kicks, not a proper thai boxer.