I haven't been too cutting edge in terms of sci-fi technologies, but thought I'd cover a few common ones.
These technologies do work:
FTL Travel and Communication
All the major races, and some of the minor ones, have developed their own form of superluminary drives, and with the collaboration of the dendaro and the gau, significant advances have been made. Also, a network of computers extends through the planets known as the League-net (yeah, more propaganda). It tends to be a prime lurking grounds for a few rogue AIs.
Nanotech
This does work, but is strictly regulated. Small matter compilers exist in larger cities, but production of free travelling nano-machines are not allowed.
Cybertechnology and Virtual Reality
This works, of course. In fact, most FTL crews function via a cybernetic interface.
Genetic Engineering and Cloning
This exists but is generally only done in secret labs in obscure corners of the galaxy. People seem to distrust genetic alteration (especially, despite all odds, the dendaro, though the whistlers don't see what the fuss is about).
Energy Weapons
Though slug guns still exist, the more commonly weilded weapons are beam weapons of some type. Also, energy blades exist, however these are not sold in many locations as the number of self-inflicted fatalities and injuries associated with these is just mind boggling.
Tractor Beams
These are available only on the largest of ships, given the energy requirements needed.
Zero-Point Energy
This is essentially the ability to draw power from the fabric of existence. I'm a little sketchy on it, but I always thought it sounded cool. The following URL has information about it.
http://www.jse.com/haisch/zpf.html
It is the foundation for the technology behind the FTL drives. Cold fusion is typically only found in outlying, primitive communities. You can imagine how strange Amber seems to Lentaro. It's like a bad episode of Star Trek.
Gravity Manipulation
Most vehicles that require any travel above ground utilize gravity manipulation, to hover, fly, enter orbit, etc. Also, on many spacecraft an artificial gravity is generated as well.
Artificial Intelligence
These are very rare and well hidden from the general population. A few rogue ones are listed in the Special Projects files.
These technologies do not work:
Transporter Technology
Holo-Decks
Food Replicators
Time Travel