The Chronicles of the Immortal God - Chapter 5: Ice Wyvern King

After announcing it will be discontinuing all service, the internet game ‘Yggdrasil’ shut down… That was the plan, but for some reason, the player character did not log out some time after the server was closed. NPCs start to become sentient. A normal youth who loves gaming in the real world seemed to have been transported into an alternate world along with his guild, becoming the strongest mage with the appearance of a skeleton, Momonga. He leads his guild ‘Ainz Ooal Gown’ towards an unprecedented legendary fantasy adventure!

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 his tragic life ended, Aleron expected to reincarnate or transmigrate, but instead, he was transported with his body and summoned as a hero...only to enter a new hell as he had trash stats and couldn't activate his Divine Blessing, prompting the King to extract his boon.He was tortured and onward to being buried alive with his soul ravaged after they removed his Divine Blessing. But all was not lost as Aleron found he had the Ultimate Gacha System at the death's door and initiated his first summon in the Lords of Arcane banner.[Congratulations! You have summoned Darzax the Graveborn, the Sorcerer of Death and Necromancy.]

She transmigrated into an orphan, thinking that she still had her boyfriend with her, yet in an instant, her world crashed. For the position of heir, he said, “Yao’er, why don’t you become my second wife?” A sentence destroyed her wishful thinking, causing her to end their relationship of two lives cruelly. Leaving the hustle bustle, she then lived in a forest, wanting to find an honest man to spend the rest of her life with. But not long after getting married, she realized that the honest man she married was a bit dishonest.