The Villainess's Secret Bedroom Service - Chapter 15: The Palace Gardens

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.

"When will people understand.... I'm only half insane?"

Jack Somnus was a mid-wealth professor of economics and a trading advisor for the powerful Johnson family. But after years of working for the Johnsons, he was abandoned without a word. He was laid off without as much as a severence package. Jack’s life got worse when he lost his wife. Depressed and alone, he got into an unfortunate accident. Instead of dying, he travels back in time to his teenage years. Now, Jack has a second chance to live the life he always wanted. He wants to be the one who controls, not the one being controlled. But his time travel hides a deeper secret, one that might throw him for a loop. [WARNING: CONTAINS EXPLICIT EROTIC SCENES]

A swordsman hailed as the strongest has reached his end, and was reborn as an elven girl.

This is the story of the swordsman only knowing how to kill in his past life aiming to be the best healer as a girl.

In the final battle against a monstrous entity with his teammates, the strongest swordsman, the Hero’s mentor and the only one in their party incapable of magic yet the most skilled with the sword, sacrificed his life to end the battle once and for all. Reincarnated as an elf girl, the strongest swordsman decided to live a different life from his blood-stained past and pursue the magic that he has never used before.

As a girl, she apprenticed under the old potion maker and healer of the village to be like someone she had admired in her previous life while keeping her condition sharp with sword training as she had done in her past life.

After learning the ways of a healer and convincing the elf village that she is capable enough of leaving for the outside world, she hitched a ride with a party of adventurers passing by the village and went out to see how the world has changed.