Jikuu Mahou de Isekai to Chikyuu wo Ittarikitari - Chapter 413 - Weight

He said coolly: “One million a month, stay with me!” She raised her eyebrows and smiled: “Pay a 30% deposit first, no credit!” Show no mercy. When the contract expired, she turned around gracefully, and when he chased after her, she found that there was already a kid the size of a kid beside her…

- Description from novelbuddy

When Song Qinghan woke up, he found that he had not only transmigrated into another world, but also… had a ball in his stomach. He thought the original owner of this body had left a total mess to him. But it turned out there was a piece of precious jade hidden in it. Looking at the six-pack abs of Wu Dahu, he rubbed his hands with great excitement. Farming, your job! Hunting, your job! Giving birth, ahem, you worked hard! But surgery… leave it to me!

“If he’s being badass, I’m gonna plant my own crops. If he messes with me, he will not live past next year.”

Homebody Zhao Hai brought ‘QQ Farm’ along in his traversal to another world and resided within the body of a fallen noble. His fief was a black land which nothing could be planted, and more importantly, he even had a peerlessly powerful fiancee, who was actually the successor of a duchy and future Grand Duchess!

Even more importantly, he is a magical and martial cripple who could not learn magic and martial arts. His crippling was very thorough.

“I can’t learn magic, but I have the farm. You dare attack me? I’ll release bugs to eat up your rations and crops, and put pesticides and weed agents into your water sources to make your lands grow weeds. See if you dare to attack me. What? You wanna hire killers to assassinate me? Hehehe. I’ll hide inside the little house in my farm and see how you can attack me. When you leave, I’m gonna terminate your country’s crop productions, and then all of your people will revolt. See if you dare to kill me.”

Watch how this somewhat black hearted hobo uses his QQ Farm in the world of swords and magic to become a globally known nightmarish existence.

- 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.