The Grand Secretary’s Pampered Wife - Chapter 648.2: Polo Tournament

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.

Han Sheng Li is the Crown Prince of the Great Han kingdom. Since the age of fourteen, he mostly went to the wars with his father, Han Wenji, the great emperor of the Han Kingdom. He's the most favored child of his father but, is the cruelest and ruthless among all of his seven half brothers.

Earth Online – a virtual MMORPG that takes place in the future year of 2190 – a game that everyone will bet their futures on. Set in a map that is ten times the size of real-world Earth, players battle for supremacy in the first game to feature personal adventure, territory construction, and grand warfare. For every death you experience in the game, your level would drop back to zero. Ouyang Shuo, an above average player, suffered the ultimate betrayal. For merely a piece of equipment, his sworn brother betrayed and backstabbed him. This time, after he reincarnated in the game, Ouyang Shuo swore to exact vengeance.

The Empire stands triumphant.

For twenty years the Dread Empress has ruled over the lands that were once the Kingdom of Callow, but behind the scenes of this dawning golden age threats to the crown are rising. The nobles of the Wasteland, denied the power they crave, weave their plots behind pleasant smiles. In the north the Forever King eyes the ever-expanding borders of the Empire and ponders war. The greatest danger lies to the west, where the First Prince of Procer has finally claimed her throne: her people sundered, she wonders if a crusade might not be the way to secure her reign. Yet none of this matters, for in the heart of the conquered lands the most dangerous man alive sat across an orphan girl and offered her a knife.

Her name is Catherine Foundling, and she has a plan.

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A Practical Guide to Evil is a fantasy series about a young girl named Catherine Foundling making her way through the world – though, in a departure from the norm, not on the side of the heroes. Is there such a thing as doing bad things for good reasons, or is she just rationalizing her desire for control? Good and Evil are tricky concepts, and the more power you get the blurrier the lines between them become.