Will anything bad happen if I just delete my thumbnail cache? I keep data on a thumb drive and sometimes my laptop gets hot running quicklookd presumably trying to make thumbnails of all of the files on the thumb drive. The high runner file types are images, pdfs and JSONs. I am guessing if I kept them zipped I could avoid the thumbnail generation but that's a different question.

I've found index.sqlite and thumbnails.data in the private folder com.apple.QuickLook.thumbnailcache. This answer may address my question indirectly but I don't really know what to do or what will happen.

If I just go and delete index.sqlite and thumbnails.data and then restart, will my computer blow up? Will it have to generate all thumbnails for files on my start-up HD again? 

I have never used SQLite so I don't think I should try to modify this pair, even with a script, and I understand that next time I use the data quicklookd may fire up again. Still I'd like to know what would likely happen if I deleted this pair of files.
This is a bit of a guess, but I'm assuming if you switch off the icon preview &amp; preview column, then the system would have no need to generate preview icons...

You might need to do this for all 3 view types, Column, Icon &amp; List, from View menu  > Show View Options  Cmd ⌘   J 
Example [using a RAMDisk, as it was just conveniently populated]...