I have Immortality In The Cultivation World - Chapter 34 -

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.

Lin Xun unintentionally downloads a text game called “Book of Salvation”.Leveling up and taking adventures is just standard procedure.Not only can he bring game items into reality, but he discovers that he can also bring game characters into the real world…Although the game difficulty is hellish, luckily, Lin Xun has an unusual talent.While other Apostles can only use one game character…Lin Xun is hesitating over which one of the game characters he should use.While other Apostles are still using weak human characters...Lin Xun is already using powerful monster BOSS characters.…Then one day, when Lin Xun brings a terrifying BOSS into the real world...“Would you believe me if I said I'm here to save the world?”

Sanctora has known peace for generations—too long, perhaps.Built upon ancient ideals and ruled by a council bound to tradition, the kingdom believes itself untouchable. But beyond its tranquil borders, something has awakened. Whispers of vanished heroes, creatures long thought extinct, and shadows that no longer sleep begin to creep back into the land.Liora never wanted to be a hero. Orphaned young and shaped by loss, all she’s ever known is survival base on love and kindness. But when a brutal invasion exposes the kingdom’s deepest vulnerability, she’s thrust into the heart of a battle far greater than herself. Her light-element magic—once dismissed as minor and passive—may be the key to a new era of power.As Sanctora struggles to adapt, Liora must decide whether to follow the path laid out by those before her… or blaze a new one through fire, blood, and truth.Epic, emotional, and filled with slow-burning revelations, Ancient Beast Summoner is a story of legacy, buried power, and the girl who just might change everything.

Imagine being forced to live, after death, as incorporeal bodies trapped in a vast space of nothingness for thousands of years, with nothing to do but exchanging past memories with other cohabitants (read: weirdos). Everybody wanted out, but there was no way to leave the Void…

Until one day, a young man was finally summoned, as a powerful but reluctant mentor, by a bubbly and motivated but completely naive young girl. Baiyi, finally out of the Void, was the only one who could save all of the other 32 souls from their prison and his summoner might just be The Key to their freedom.

However, Baiyi had to use the techniques and abilities the other souls had taught him throughout the years, and together with his own extensive knowledge of anime and game tropes from his shady and dangerous past as an otaku, to face the biggest challenge of them all: training the clumsy young girl he was forced to partner up with… into a competent sorcerer!

This is a story of heroic adventures, cunning strategies and romantic tales. How will our MC thrive in a world completely strange to him? Where will his ambitions and abilities take him in the palace?

- Description from Novelupdates