Is there a complete list of the current appearance modifiers out there? Further, is there knowledge (or has there been science) on which of the existing modifiers work where (e.g. applying the BROAD_CHIN or DEEP_SET modifier to, say, the neck or a wing)? I've seen others mention the ways to effectively make custom descriptors, but am curious as to what is baked in by default. I've done some searching through the wiki and forums but have only found some '& etc.' example lists, nothing claiming to be complete.
On a somewhat related note, is it possible to effectively increase the size or thickness of a layer or body part via appearance modifiers? I was tinkering with the idea of a creature with thickening scales (or other natural armor) at certain ages via APP_MOD_RATE to the size-linked modifiers (BROADNESS/HEIGHT/LENGTH, according to the wiki). This would be opposed to just getting bigger in general (i.e. having a burst of SIZE growth at a certain age range) or just having naturally thicker scales in general via a combination of body detail plans (thicker relative size for scales, thinner everything else) and overall larger size.
I've noticed the above works for things like the general body allowing one to create a race whose adults are always described as "enormous" or "gigantic," but it's tougher to tell if it's working for net thickness of individual layers or size of body parts. I tried fiddling with the FAT and MUSCLE layers as a test of sorts, but making those larger doesn't seem to trigger the fat/muscle descriptors (though it will note e.g. "incredibly broad" fat/muscle on the upper lip - why just the upper lip when using [SET_TL_GROUP:BY_CATEGORY:ALL:{FAT/MUSCLE}]?).
And, related to all that, would having a larger layer via size-linked appearance modifier 'growth' actually make it functionally thicker for combat purposes?
Does APP_MOD_RATE accept negative rate values? E.g. elderly people getting shorter? I'm guessing not, due to the potential for negative overall values, but figured I'd ask.
Finally, as a person who just recently got interested in modding DF I feel I must additionally give thanks to the various folks who helped build the wiki and answer questions like this - there are enough resources out there that fiddling with the raws is pretty darn approachable. So thanks, and apologies for the barrage of questions.