That was very common years ago when the price of bitcoin was low, people bought bitcoin and they did not thought much about it and they forgot about their coins but some time later they realized the price of bitcoin had gone up dramatically and they wanted to get those coins back but since they did not took enough precautions to recover those coins they lost access to them, however I believe such scenario is going to become less common as the value and the potential of bitcoin as a currency becomes more widespread to the general public.

Sorry, but it looks like a list filled with scams, is there anyone who is able to verify all those stuff?

It was about 2013. 
I had a couple of hundreds worth of BTC & LTC. I used my GPU for mining (believe it was r9 280X?), and one day I came back from work and found all up in smoke.
PC was gone, hard disk deceased.
I had a PK printed out on paper, and I thought I was safe there. I was sorry for the PC, but glad that my apartment didn't catch on fire.
At a later date, with a new PC, I started to install all my shit, got to a wallet.
I went to the drawer where I held all my PC related crap and found out that my girl (now wife), has "cleaned" everything for me, after that terrible fire.   

I was too furious to get in crypto until early 2017., but a lesson learned.
NEVER EVER have PK only in one physical place...

When I am still newbie, I created a bitcoin wallet at that time so I can store my bitcoins that I am going to use for online gambling. And what happened was I forgot my private key as I thought that it is not important because I was thinking at that time that I only need my email address and password to login. I try to recover my wallet via my email but I was unlucky.

It was my big mistake as I have stored 1 bitcoin to that wallet but the bitcoin price at that time was around 220$, after the incident I transfer to our local exchange and I always make sure to save the private key in every wallet that I created so I can avoid my past mistake.