Imperfection - S7-E2
Continuity mistake: Tom Paris is already wearing his wedding ring in the scene where he is assisting the Doctor with Sevens operation. He doesn't get married until the next episode.
Continuity mistake: When Neelix shows Torres her own quarters, her bat'leth can be seen in the background. It's a run of the mill bat'leth, unlike the one she actually hung up in 'Prophecy', which was gunmetal and had a spike in the middle.
Continuity mistake: When Seven takes the mobile emitter off, it alternates position a few times. First, it's right side up. Then upside down in the close up, then right side up when the Doctor appears.
Repression - S7-E4
Continuity mistake: In the theater, the assailant's hand goes from a few inches away from the Tabor's position, to touching Tabor's position.
Continuity mistake: In season 6 episode 10 'Pathfinder', Admiral Owen Paris has the rank of Full Admiral. In season 7 episode 6 'Inside Man', the same Character is seen as being only a Vice Admiral. In the season 7 season episode 'Endgame', the last episode of the show, he is once again seen as being a Full Admiral.
Answer: If you include the original Star Trek series (1966) then there are several. The communicators used in the original series were before (and said to inspire) mobile phones. We currently do have teleportation technology but it currently only works on things the size of a few molecules. A "Cloaking device" also exists; it's a fabric that bends light through it, though it currently only works in infra-red. The Hypospray is real and was patented in 1960 - six years before the original series aired - it's actually called the Jet Injector. Faster Than Light travel is still a few decades off, but there are several real-world theories that look promising, including one that is remarkably similar to the method used in the Star Trek Universe called the Alcubeierre Drive that involves manipulating spacetime ahead and behind the ship and the ship "riding" it. Medical techniques and technologies have also advanced considerably; prosthetics particularity and we routinely have robots performing surgeries where absolute precision is needed. The "Shield" used in the series have a few primitive versions around. The Phasers used in the series are used but are not very powerful (nor will they ever be as powerful as the Star Trek version the laws of physics gets in the way) but rail-guns (using magnets to spin then propel a projectile) and particle accelerators like the Large Hadron Collider have been around for a while. The Replicator would require a nuclear fusion reactor and a nuclear fission reactor in something the size of a large oven and the Holo-deck wouldn't work at all based on our current understanding of physics so those are both still science fiction at the moment, but who knows!
Sanguis