Please make sure that faerie will be there as a source of faerie dust.
This could be further mixed with steel to create faesteel - something just as good but lighter than original steel.
Similar arrangement with animal people, maybe a way to mutate normal animals into sapient citizens.
I wasn't exactly sure how I'd handle animalmen, but this is a good one assuming DFHack cooperates.
Cooperates.
My current fort has Hippo Man Sentinel and two Elephant Men Heavies guarding it from harm.
create-unit allows you to generate fully fledged fort citizen of any race.
Btw you should see what properly trained Elephant Man can do to intruders, when armed in full plate, tower shield and with a platinum maul.
Although the only valid metal to make armours for them is mithril - full plate set of steel weights like 1k in total.
But still. All of the sudden all those minotaurs and jotuns seem to be *somewhat* less dangerous.
Perhaps a building that would allow an elven noble to make "an offering to the beasts" and use meat to summon lion men or plants to summon elephant/hippo/rhino men with some small chance (think of Meph personal shrine building) would be good here.
It would also have a good impact on fps - people would utilize their food stacks.
Just keep in mind Animal Men have to have their [MEANDERER] tag removed otherwise they will not function correctly.
Weaponized enchanted psychedelics, ranging from making enemies get dizzy to changing their perceptions so thoroughly that they actually become groups of assorted wild animals and scurry away.
This I don't know. I originally planned to add some poisons, but Meph thought it wouldn't fit a race that was supposed to be good.
Succubi have this.
Besides these do not have to be poisons, but a fae dust with some *extra* components.
Different castes based on the season they were born in, perhaps a transformation interaction they can use as soon as they turn 1?
This, while neat, would require Roses (or some other hack wizard) to whip up a script to do that.
Not sure if elves should be caste society. Plenty of castes to go around already in all those races.
I am not sure if it would be a very good idea to modify elves so far from vanilla. They are good as they are, perhaps just add them some elvish magic (like fae dust above) rather than to rebuild them from scratch.
That being said.
Elves come in different types. Wood elves, high elves, grey elves, dark elves, etc.
Being "good" doesn't mean being defenseless, fantasy elves have long history for violence and warfare.