As you discover "troves" in the caves, you earn "discovery achievements" for them. For instance, when you find your first Cave Fungus, you'll earn that achievement at level one. The next time you find one, you go up to level two, and so on.
As you can see in the screenshot above, you also get a perhaps-poorly-named "achievement" whenever you die, allowing you to compare the good stuff you find to how many times you bite the dust.
Like selfies, achievements carry over from game to game, so that as you explore more caves, you get "credit" for making more and more discoveries. This also serves as some interesting statistics about how many different things you have found, and their relative rarity over time for you.
For those of you worried about preserving permadeath, achievements do not affect gameplay at all. They're just for interest's sake.