According to the citizen detectives of the r/unresolvedmysteries community, these are the cases that should be closed.
Three fellow students escorted Smart back to her hall of residence after a party.
Her disappearance is an actively investigated missing person case.

Kristin Smart Family
Cadaver dogs were brought in to search through campus dorms.
The dogs picked up the scent of a deceased human on the corner of Floress mattress.
Also, Flores was noticed having a black eye on the days following Kristins disappearance.

He told investigators several different stories about how he received the injury.
u/mcwjdw33
Update:On April 13, 2021, Paul Flores was arrested and charged with Kristins murder.
Simpson, and 26-year-old Goldman were found stabbed to death outside of Nicoles home.

FBI
Since civil lawsuits dont require proof beyond a reasonable doubt, its impossible to say whether O.J.
u/mcwjdw33
Patricia Adkins
Had an affair with co-worker.
Lent him close to $100k.

Wikimedia
Asks for it back.
He invites her on a camping trip.
She never comes back.

Crime Watch Daily Youtube
When questioned he claims to not even know her, though its proven he does.
No body, no case.
He walks away a richer murderer.

YouTube
Not even shamed publically, because police withhold his identity.
DecadentEx
The Dupont de Ligonnes case
France, 2011.
The whole family was found dead, burried under the terrace, except the dad.

Collier county sheriff’s office
Weeks before the murder he had inherited his dads 22 long Rifle and started going to the shooting range.
The bank accounts were closed, the lease on the house ended, etc.
He was last seen on a surveillance footage in the Var, and was never ever heard of again.

Where is Kristine Kupka?
So yeah, and the crime remains unsolved.
Neither man has been seen or heard from since.
He was named that because sketches of the victims would often be found near their bodies.

San Francisco Police Department
ThatEnglishKid
Susan Powell
Susan Powell.
I highly recommend Dave Cawleys podcast Cold about the case, even if youre familiar with the case.
sh4nn0n
My aunt
Personal, but my Aunt.

Wikimedia
Lived with scumbag boyfriend after leaving strict conservative upbringing.
She was paying her way through nursing school by dancing at less than reputable establishments.
Boyfriend was older and abusive.

Wikimedia
She was packing a bag one night, supposedly to leave.
One a few minutes later of him saying she shot herself.
She was shot in the temple, and was braindead, removed from life support a week later.

No one did anything, not the cops or family.
No one pursued it and dude just dipped town.
They even ended up asking how (boyfriend) was.

Andreas Biegleder
They were all buddies.
As of now, Martha Moxleys murder is technically unsolved.
They have been trying to nail him for years, but much of the evidence is circumstantial.

YouTube
Police ruled it a suicide.
The only other person at the mansion was her brother in law.

Lauren Spierer