Most Amazon filler items are pure junk that you buy solely to reach the $25 point, in order to get free shipping. Here's one that's actually useful.
It comes in several strengths for different purposes, red, blue, purple, green, and an oil resistant blue. There's also a copper anti-seize lubricant.
Rather than list all the types separately I'll just list the complete product page. Look for the ones that cost 95 cents.
If it seems a bit small compared to Loctite or Permatex brand threadlockers, it's also true that most people don't need 6ml of the stuff. This is the "just right" size at 2ml.
Why spend 6 bucks when you don't have to?