i'm just going to drop in and say I have done a mega ton of research on 3D printing in preparation for buying my own printer. (it's partly why I've been quiet on the forum.)
Here are a couple things that would fit with lizardmen. FYI, not all STL files are released free, some you have to pay for.
Fat dragon games - all thier stuff is made to be printed on a FDM/PLA filament printer. they specifically design thier stuff for the $220 ender 3/ender 3 pro, but you can print it on anything, as per usual. UNUSUALLY however, they are made to be support free, which means more miniatures and less hassle.
http://www.fatdragongames.com/fdgfiles/?p=4888
Dungeon print has his Aztlan sets:
https://www.drivethrurpg.com/browse...aDdmaSqNg-vkFx78z7l5Qrg2ZM1nbnLnVc4CEYrHuyww4
https://www.drivethrurpg.com/product/270729/Aztlan-5?src=newest