Why plants and trees have good and evil tag?
In Vanilla, they have these tags to restrict them to only appear in specific biomes (Sun Berries, for example, only appear in GOOD biomes). Unfortunately, IIRC, this is broken in X.25, and in my experience these plants do not appear
at all.
I like to plant Sun Berry seeds I get from the elves in order to produce Sunshine for my dwarves to drink. Without the elves being able to bring me Sun Berries, this goes out the window. As such, I removed the tags to allow these plants to appear anywhere. It's a side effect of something broken in this version, and often times it's one I forget to add if I 'reset' my changes, since it's not as important to me as kobolds or aquifers.
Teeth you can already decorate things with, hooves as well. It's just miscellaneous things like scales and feathers that don't do anything.
Yes, I know - but adding "shell" to these makes them usable for moods... like in the desert, or a purely mountainous area, which may not have access to shells. You cannot, sadly, import shells for use, which makes them unpleasant weaknesses in my 'ideal' resource setup, to say nothing of being slightly unrealistic. (If there's a demand for shells, why doesn't anyone export them?)
...and before someone asks: No, it's not 'more realistic' to have a single alligator scale being used as a shell, but it's also not particularly realistic to have no one exporting a demanded trade good - shells are fairly light weight, and would be worth their weight in metals to me in some cases (like for moods). I'd request them from the mountainhome, humans, or even elves, if I could get them.