Elenopsis ebano (Pithecellobium) or Texas Ebony has a most unusual structure when it is young and so a delight to those who want to add variety. Theis very hardy evergreen tree is slow growing but adds a nice accent to desert landscapes.
Eucalyptus microtheca - Blue Ghost Eucalyptus; Rapid growing and beautiful. The leaves are fragrant and the tree is very tolerant of desert soils and heat. This tree may be damaged by severe cold where temperatures stay below 18 degrees for any significant amount of time.
Fraxinus angustifolia - Raywood Ash Tree; Very attractive shape, a bit taller than it is wide. The dense canopy and foliage produce super shade for hot summer days. Not as fast growing as some of the other Ash trees but attains a 25 to 30 foot height within 10 years or so. Hardy to zone 3.
Fraxinus velutina 'Glabra' (deciduous) - Modesto Ash Tree. A great shade tree for any large area in the desert southwest. This deciduous tree will rapidly grow to 30 by 30 feet or more, giving the shade that is so much desired in our climate. The Fan-Tex Ash Tree is very similar to the Modesto. The leaves are larger and the canopy is wider. 
Gleditsia triacanthos inermis (deciduous) - Thornless Honey Locust has an open & fast growth habit to approx. 30 x 30. Slow to leaf out in the spring and early to drop it's leaves. Seed pods can be a clean up issue.
Koelreuteria paniculata (deciduous) - The Goldenrain Tree is very attractive as well as adept to the desert climate and soils. Moderate growth rate to 25 x 30 when mature, this tree will provide great shade for our long hot summers.