Doomsday: I Obtained A Fallen Angel Pet At The Start Of The Game - Chapter 182 - Slay the Energy Demon!

Lu Chengye’s dream was to live freely and have fun until he died. Unfortunately, he inherited a company and was worked to the bone!

After finally taking over the company, he had just prepared to begin his carefree life when he was hit by a car and died. His last thoughts were that it would be much better not to be human in the next life.

And so, Lu Chengye was reborn as a Labrador.

- Description from Novelupdates

A scientific genius named Thomas Harrier was transmigrated to an imperial prince body after a car accident that took his life. He found out that he is in a world similar to our own with a timeline akin to early twentieth century. The body that he is occupying was the imperial prince of a failing empire who suddenly rose to power after a successful assassination attempt of his father. Unaware that the attack is just the beginning of what is to come. He faces many challenges throughout. Will Thomas Harrier be able to live his second life in peace while running an empire and getting it back to its former glory? Or will he succumb into a conspiracy lurking within the country's borders?

Expect some:

Cold war era techs.

Super battleship with advanced electronics, propulsion, and fire control systems?
Helicopters?
Missiles?
Modern medicines and equipment?
AC-130?
A nuke?
Challenger or Abrams or Leopard?
F-4 Phantom or MIG-21?
Colored TV's.

Everything!!!

PS. Cover not mine, I just found it on google.

After living in a desolate land, where there wasn’t even a single blade of grass and hunger was an everyday reality, Min Sung finally returns to Earth: his home.

The MC entered the body of the An family eldest son, An Ziran, an arrogant 16 years old boy who weighed 78 kg (~171-172 lbs), who only knew how to eat, play and sleep. Seeing his current body, An Ziran decided his first priority was to LOSE WEIGHT!