Kala Jeera (Bunium Persicum) is a member of the parsely family and is sometimes refered to as black cumin (not to be confused with nigella). It is sweeter than cumin and posesses a floral, camphorous flavor with cardamom overtones. Toasting somewhat diminishes these flavors and brings forward an earthy, nutty taste. Don't be put off by the scent of these seeds (the sales lady decided that it smelled like a monkey cage), they really need to be chewed or broken to release their flavor. I can see this being used in both sweet and savory preparations.
Mahlab (Prunus Mahaleb) these are actually the dried kernel extracted from the inside of a Mahaleb cherry pit and belong to the Rosaceae family. They have a floral, bitter almond taste--think marzipan with a hint of rosewater. There is a slight bitterness to them, although not unpleasant. They are widely used in Southeast Europe and Western Asia to flavor sweet breads and cookies.
Sumac (Rhus coroaria) these ground berries have an astringent vinegar scent with a pleasantly sour taste and are commonly mixed with sesame and thyme in the popular spice mix Za'tar. It will be interesting to play with this isolated flavor.