Here's a preview of the unique buildings:
Stasis Chamber (Vaadwaur, replaces Hospital)
Stores 50% of food after growth
Only 1 allowed per system
Cultural Exchange (First Federation, replaces Library)
+1 additional scientist
Heater (Gorn, replaces Recreation Facilities)
+1 additional health
+1 additional happy
Defense System (Tholian, replaces Planetary Defense Grid)
Units build in city can see cloaked ships
(note: because of this, the Dominion UU is being reduced in cost)
Agony Booth (Terran Empire, replaces Jail)
-75% war weariness, no spy specialist (but other espionage effects still apply)
Labor Center (Alliance, replaces Factory)
+1 additional engineer
I've also added another tech; I'll reveal it with the UUs since it would fit in better with that preview.