I'd like to nominate all of these..
Parallax - Voyager is trapped in a quantum singularity's event horizon.
The Cloud - The crew enter a nebula to collect samples before realizing it is a living organism.
Ex Post Facto - Tom Paris is framed for murder on an alien world, and Tuvok must work out the truth before Paris's mind is shattered by his punishment: reliving the murder from 'his' victim's perspective every few hours.
Heroes and Demons - The holographic doctor must rescue crew members who were turned to energy in the Holodeck, by entering a holodeck program of Beowulf.
Faces - B'Elanna Torres is split into her human and Klingon halves by the Vidiians.
The 37's - A group of humans from the 1930s is found in stasis on an abandoned planet, including the lost Amelia Earhart.
Elogium - Space-dwelling life-forms cause Kes to enter the Ocampan fertile phase called Elogium, putting pressure on her relationship with Neelix.
Parturition - Neelix and Tom Paris fight over Kes, but are sent on an away mission together.
Tattoo - Chakotay encounters non-humans that have the same tattoo on their foreheads that he has.
Threshold - Tom Paris breaks the transwarp threshold in the Shuttlecraft Cochrane, designed to reach warp 10, but there are some peculiar side effects.
Dreadnought - A highly advanced Cardassian AI missile that had been reprogrammed by B'Elanna Torres is found in the Delta Quadrant
Innocence - Tuvok crash-lands on a moon and finds children who have been abandoned.
The Thaw - The crew find aliens mentally connected to a computer that has created a being that feeds on their fear.
The Chute - Tom Paris and Harry Kim are trapped in a prison.
Warlord - Kes is controlled by an alien warlord named Tieran.
Rise - Voyager helps a planet with asteroid problems. Tuvok and Neelix crash-land on the planet and attempt to fix a maglev space elevator.
Favorite Son - Harry Kim is contacted by a planet full of women.
Real Life - The Doctor creates a family on the holodeck.
Concerning Flight - Aliens steal several key components of
Voyager, which are retrieved with assistance from a holographic Leonardo Da Vinci.
Mortal Coil - Neelix dies in an attempt to sample proto-matter from a nebula. Seven of Nine believes she can revive him using Borg nanoprobes, but Neelix finds it hard to adjust, particularly given that he has no memory of an afterlife of any kind.
Extreme Risk - B'Elanna purposely puts herself into increasingly more dangerous situations. Meanwhile the crew decides to build a new shuttlecraft, the Delta Flyer.
Once Upon a Time - Neelix looks after Naomi Wildman when her mother is injured on an away mission.
Nothing Human - A wounded alien is brought on board from a stranded vessel and attaches itself to B'Elanna Torres.
Bride Of Chaotica - Paris' latest holodeck adventure The Adventures of Captain Proton takes an unexpected turn.
The Fight - Chakotay lies in sickbay as he attempts to communicate with aliens through hallucinations.
11:59 - Janeway reminisces about one of her Earth's ancestors, Shannon O'Donnell from Indiana.
Barge of the Dead - B'Elanna's shuttle is hit by an ion storm and she awakens to find herself among Klingons in the Barge of the Dead, on the way to Klingon Hell.
Tsunkatse - Seven of Nine and Tuvok are kidnapped whilst on shore leave, and Seven is forced to fight in a gladiatorial contest to the death.
Good Shepherd - Three crew members who are under-performing are taken on a mission by Janeway.
Muse - Torres is stranded on a bronze-age planet after a crash in the Delta Flyer, and Kim is missing in an escape pod.
Natural Law - Seven and Chakotay are stranded on a planet with primitive humanoids.
That should do it.'Threshold' is bad, but one's like 'Barge of the Dead', and 'The Fight' are easily more unwatchable.