In Breath of the Wild, there are different variations of some of the monster types in the game, usually determined by colour. These are primarily Bokoblins, Lizalfos, Moblins, Lynels, and the Hinox.
Apart from the Hinox, these monsters seem to "Level up" as you progress through the game, appearing as blue, black, and silver variants. In particular, I generally avoided the Lynels (for obvious reasons), until very late-game, where they all (apart from the one on Ploymus Mountain, which appears to remain as a default Lynel) were Silver Lynels.
I have been trying to do my best to fill the Hyrule Compendium 100%, which would include all of the Lynel variants, and the Lynel variant gear. So that would mean I'd need to get all of the default Lynel gear, the Mighty Lynel gear, and the Savage Lynel gear.
So, what "progression" in game causes the appearances of higher level monsters (health/story?) and is there any way I can find lower-tier variants once the higher-tier monsters appear?