First Encounter with U.S.S. Equinox - The U.S.S. Equinox was a Federation starship pulled to the Delta Quadrant in similar fashion as Voyager. However, the Equinox encountered not the Kazon, but the Krowtonan Guard, a malicious species who slaughtered nearly all of the Equinox's crew. After escaping their space, the remaining crew came in contact with the Ponea, and eventually were given powers to  take hostage subspace aliens who, when killed and boiled down, emanated pure antimatter, which the Equinox harnessed to improve the warp drive - within weeks they had travelled tens of thousands of light years. Voyager encountered the Equinox and learnt of its secret, and now Janeway must stop them from slaughtering anymore of the subspace aliens. (Voyager episode "Equinox")

Sentient Bomb - Voyager encountered a bomb with an artificial intelligence. It was only one of many. It took over the Doctor's program for a period but later destroyed itself to save civilisations from destruction. (Voyager episode "Warhead")

U.S.S. Relativity - Voyager was destroyed by a "time bomb" from the 29th Century which had been placed in Voyager's past, set to detonate in a few years time. Seven of Nine was rescued by a ship from the 29th Century (the U.S.S. Relativity) and sent back to find out where the bomb was. She was killed a number of times, and eventually Janeway was recruited. The timeline reset and Voyager wasn't destroyed, but the crew were allowed to keep their memories because the time distortions were artificial. (Voyager episode "Relativity")

Kati - Devout people who engage in prayer and religious rituals many times a day. (Voyager episode "Someone to Watch Over Me")

The "Think Tank" - Under terrible attack, Voyager turns to a group of aliens called the "Think Tank", who are renowned for solving tricky tasks. The group have solved many mysteries, including the terrible Vidiian phage virus. Their demands may be excessive, however; in return for helping Voyager they wanted only one thing: Seven of Nine. (Voyager episode "Think Tank")

Chaotic Space - A region of space where the laws of physics have no meaning (For instance, Voyager appeared to be existing twice in the space-time continuum at the same time in different areas). Very dangerous region. (Voyager episode "The Fight")

Deuterium debris field - Voyager rushed to the assistance of a vessel in distress, but were apparently too late, as all they found was a debris field composed mostly of liquid deuterium. It is unknown what ship was in distress. (Voyager episode "Course: Oblivion")

Editor's Note: Of course, we the viewers know that the debris field was the remnants of the alternate Voyager created in the episode "Demon" (Season 4). The alternate Voyager had developed an advanced Warp Drive, and came within 2 years of Earth, but had to return to the Delta Quadrant in order to survive. Unfortunately, they did not make it back to the original Demon planet in time.

Varu Generational Ship - The Varu built a generational ship overtime to keep themselves away from others. They required Voyager help to repair sections of the framework which had become damaged. (Voyager episode "The Disease")

Borg Sphere/Transwarp Jump - Captain Janeway decided to try and harness the power of a Borg Transwarp coil, obtained from a damaged Borg sphere. After several complications, the coil managed to propell Voyager 15,000 - 20,000 light years toward home, shaving around 10 - 15 years off their journey.

* It should be noted that Voyager is still in the Delta Quadrant at this time. (Voyager episode "Dark Frontier")

Masquerading creature - A giant, highly intelligent space creature was discovered to be masquerading as an avenue home for the Voyager crew. It altered the crew's thought patterns, taking advantage of their desires to return home. (Voyager episode "Bliss")

Gravity Well - A Voyager shuttlecraft became lost at the bottom of this sinkhole in space, where time works differently at the bottom than at the top. A barren planet is at the bottom, where Tom Paris, Tuvok and The Doctor were stranded for a period of time. (Voyager episode "Gravity")

Subspace "sandbar" - Voyager, whose engines run on a subspace field, became stuck on this phenomenon in space, unable to move. However, they eventually worked free. This phenomenon may have something to do with the aliens that phased into the holodeck. (Voyager episode  "Bride of Chaotica!")

Devore Imperium- The Devore claim a great region of space, covering hundreds of light years. Devore are frightened of telepaths, persecuting them on-site and inspecting vessels that pass through their space. (Voyager episode "Counterpoint")