My Demon Tyrant And Sweet Baby - Chapter 2743

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.

The world experienced a cataclysmic change, and countless spatial gateways appeared out of thin air.

Exotic beasts of all shapes and sizes swarmed out of those aforementioned spatial gateways, forcing the humans to face the crucial moment for their survival.

In order to search for a chance at survival, brave warriors from the army and scientific researchers risked their lives and entered the world beyond the spatial gateways. To their surprise, they discovered that there was a chance of obtaining beast cards by killing these exotic beasts in their world.

Those with extraordinary spiritual strength are able to utilize the beast cards, perhaps transforming the cards into the beasts’ combat bodies while they were still alive, or transforming them into weapons or defensive gears, or…

A new occupation came into existence following the changes, known as beastmasters.

A transcender with two souls fused into one found himself in this magnificent new world full of waves, rising step by step as he ascends into the seat of a godly beastmaster.

- Description from Novelupdates

The worst student of Westroad Academy. The disgrace of the Blake House. A new soul enters the body of Frey Blake, who couldn’t overcome his miserable life and chose death instead.

Before rebirth, she was weak and it led to her losing 20 years of experiencing true love because of misunderstandings.

After rebirth, Su Nuo boldly declared her sovereignty: “Gu Chenglan is mine.”

Young Master Gu immediately raised his hand: “Yes yes, my wife is saying the truth.”

Young Master Gu swore an oath: I am a very principled man! Pampering my wife is my only principle. It’s that kind where there’s no bottom line.

Su Nuo’s famous remark: Unexpectedly, I’m suitable to be the richest man’s financial adviser and not only a good doctor. Even if you give me all you got, my family has me!

- Description from Novelupdates