I Started To Gain Sentience In An Eroge - Chapter 43

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.

It’s a affair between a loyal dog servant and his master.

- Description from Novelupdates

A normal person, Xin Yun, received a second chance by transmigrating to an unknown world. But because he chose to indulge in women, he lost his chance to become the most powerful.

When he gets caught by the force a struggle between the nine most powerful experts, something unbelievable happened, or it could be said that a miracle occurred. Xin Yun was reborn and sent back to the place he had transmigrated over to.

Having been reborn, Xin Yun decided he wanted to become the strongest being together with the three top experts from his previous life: the most beautiful dragon- Sparkling Butterfly, Yi Luo Xiang, the cruel dragon- Evil Empress, Yan Qing Ying, and the most dazzling dragon- Peac*ck King, Ming Xuan!

Furthermore, he wanted to pursue love with the most beloved person from his previous life- Yi Luo Xiang! Xin Yun, making use of his good fortune, used his memories from his previous life to prioritized becoming friends with Yi Luo Xiang, Yan Qing Ying and Ming Xuan. He even received a godly artifact from his previous life- the Heaven Splitting Axe!

- Description from Novelupdates

He was the cold-blooded prince of the Jin country. Decisive and smart, he had looked down on the world with apathy and disdain.

She was his Wang fei, a person who had saved him in the past, but even he wouldn’t look at her.

When the fire raged and death claimed her, it was only then that she realized her existence was nothing but a joke from the beginning.

She opened her eyes once more after spending two years as a roaming, vengeful ghost. In this lifetime, Ye Zhen promises that she will be a different person. With a slight smile, she will ruthlessly trample on those who had schemed against her and lied until her demise!

Most importantly, she would let him experience the pain of an unrequited love; the bitterness of seeking something you cannot obtain!

- Description from Novelupdates