In LOTR with Harry Potter system - Chapter 91: Flying Broomstick

Shen Yaowei was an idiot her entire life, and was finally sent to death by the person she trusted the most. After being reborn, Shen Yaowei was no longer silly. She just wanted to cling to the future tyrant and live a life of luxury. Possessing almighty skills and being known as a foolish girl, Shen Yaowei pretended to be an idiot and went on a killing spree, abusing the scumbag until he cried for his mommy and daddy. Anyone who stopped her from clinging onto the tyrant would have to die. Soon, everyone discovered that the frightening Prince Li, who had always been a loner, had changed. There was always a small shadow following behind him. “Ninth Uncle… I don’t have the strength to walk. I want you to carry me…”

the little shadow spread her arms towards His Highness, looking pitiful. “Yaoyao, I’m strong so I’ll carry you!” her elder brother, leader of the martial arts alliance, arrived at the battlefield instantly. “No, I’m stronger! I’ll do it!” her second brother, a miracle doctor, came forward. Then her third brother, fourth brother, fifth brother… All the bigshots had arrived, asking for hugs and to let them carry her. “All of you, get lost! That’s my darling daughter, so I’ll carry her!” Her father, a great general protecting the country, rushed as fast as possible to Shao Yaowei’s front, only to find that the aloof, noble and peerless prince had already knelt with his back facing Shao Yaowei. “Come on, Yaoyao. I’ll carry you.”

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 being a young master for more than ten years, he was reborn overnight became a ger who had nothing. This ger was still a lunatic!

Crazy people were hated in the tribe! He was also bullied and robbed! In the end, he was forcibly betrothed to a beastman that he didn’t even recognize.

After accepting the facts tremblingly, Wang Jin began to use the golden finger to reverse the adversity.

Being disliked by others and then becoming everyone’s favorite, snatching back everything that was robbed, as for… the beastman who was forced to marry…

Wang Jin looked at the man who had been standing by his side, and the man felt his gaze, looking back at Wang Jin, his indifferent eyes suddenly became warmer. He stretched out his hand and clasped Wang Jin’s ten fingers tightly, and said softly: “In this life, I only want you alone, no matter whether you are a little lunatic or not.

Wang Jin’s heart skipped a beat.

Forget it, this man… is quite interesting, so let’s keep him!

Years later, Wang Jin was pregnant with a big belly, gnashing his teeth with hatred when he saw the gentle and flattering man in front of him.

We agreed to only be together, and never get pregnant!

A man’s mouth, except for himself, was a deceiving ghost!

- Description from Novelupdates

[Complete 1V1 Pure Romance] Zhong Xiaoxiao had transmigrated. When she opened her eyes, she found herself on her wedding night, “You might as well prepare to be a widow.”Before she could understand what was happening, her cheap husband had fled, and she became the vilified and reluctantly married country bride. Life is like a dream, but one must carry on. So what if her reputation was in tatters? Rolling up her sleeves, she set to work with her whole family. When they met again, even if they couldn't get a divorce, acting as a fake married couple was still an option, right? However, as she continued to pretend, she actually fell... [New recommendation “Reborn Husband Tender Wife”]