Org. that administers PSATs and GREs

• "District 9" extras
• "Roswell" regulars, briefly
• Sci-fi invaders, for short
• Space aliens
• UFO flyers
• Xenomorphs, e.g
• Space invaders, briefly
• Saucer travelers, for short
• Some characters on TV's "Futurama," briefly

Wikipedia Word definitions in Wikipedia
ETS is an abbreviation of: