Here's some ideas:
Courage, Valor: Giant, intimidating creatures, as these are the ones that get associated with courage. Also animals associated with courage, though I'm not sure which ones are. No area effects due to this sphere.
Creation: Add a purple mineral called "Primordial", that occurs in every level as veins in this biome. Primordial is a rock, average wieght, highest max-edge, and other varied properties. It has high value, because it's rare. Dwarves cannot, without magic, make other elements from this.
Depravity, Misery: Blood rains, some of the current evil effects go here.
Dreams: Fanciful creatures can be found here and only here.
Food: Only edible plants. Bigger animals tend to spawn here. More plants. Above ground food crops can grow underground.
Fortresses:I think creation time fortress biomes should be large settlements that are created and abandoned at year 0. Entities can move into these just like they can other abandoned sites. If unoccupied, they can be embarked upon.
Freedom: Locked doors don't work. raised bridges work like retracting bridges. Flood gates don't work.
Lies:
Global effects: Coffined or memorialised dwarves may come back as ghosts here. Bookkeeping works slowly here.
Interactions: Areas of darkness that spawn randomly. They are impassible, but harmless. Anyone caught inside is fine, but cannot move around. Gives bad thoughts. Fake walls that spawn randomly, and mess with path finding. Fake floors that mess with pathfinding, but any dwarf that goes on them will fall. Unlike the other two, these are dangerous.
Wildlife: In additional to normal wildlife, ghost wildlife roams the land. These aren't really ghosts, but they act like it.
Love:
Some mythic creatures and animals associated with love here.
Peace:
Mythical creatures associated with peace. These tend to be docile. Similar to current good areas.
Moon:
Ware transforming area effect. Garunteed way of becoming a ware creature. Enjoy your ware-forts.
Murder:
1 in 1000 chance that a given humanoid here will die in a given year. Nobody will settle here (except players). I wouldn't wanna stay here very long.
Salt:
All water is salty. No plantlife. No crops will grow. Rock salt is likely to be found here. Elves, dwarves, and humans won't settle here because they can't grow food. They might make tombs here, or have other sites. Bandits have no problem with it.
Silence:
You can make noise here, but it doesn't travel far. Otherwise it's hard to imagine a fort functioning without differences; nobles need to talk to work. But Noise would not carry, so you can build your bedrooms near your tree farm.
Theft: All creatures get [CANOPENDOORS]. Item not in use may magically vanish. Entities would not settle here.
Torture: Sentients get random wounds, bad thoughts. Entities would not permanently settle here, except maybe cults of Torture.
Trickery: Fey are found here. Gremlins too.
Day, Night, Twilight:
These all have perpetual time of day. This doesn't have much effect on fortress mode, except no nocturnal and diurnal animals for Day and Night biomes respectively. In adventure mode, this is a noticeable effect, particularly when entering or leaving such a zone. Bogeymen come out in night zones at all hours.