Isekai / RPG game like / Fantasy World fever

MC died after being overworked and wished to be reborn has a rich family dog so to never have to work again. His wish was granted, as he woke up in a fantasy world.
He grew bigger than a human real fast and can even shoot laser beam from his mouth... yep just an average normal puppy... right?

I love it just for the pet MC (ch1 only)
If MC is changed back to human form so he can have romantic relationship with his harem I'm slamming the door though.

Recommend

A mid-rank soldier who died during the Demon race invasion, woke up back in his past as a baby. To avoid the chain of tragedy of this war (lots of dead him included), he will prepare for it with maximum efficiency.

MC was OP in 1st chapters but went back to strong “only” later on. Other characters are interesting and unlike most Isekai, strength level is quite balanced. Like MC isn’t always the one shining or leading even if his here, in a good way.
Child Mc but not fluffy.

A spin- off based on the Novel. I highly recommend the anime or the LN.
About 3 teens (1boy and 2girls) with unique abilities, bored of their respective world. After receiving an envelope inviting them in another world ruled by games (The adventurer quest types of games), they are asked by Black rabbit to join and help a "no name" community.

This spin-off about a side adventure were they ran away from black rabbit chan because of their boredom.

Young MC found a demon kid girl with the mark of a criminal and became her over-protective guardian.

He is young but renowned aventurer. She is well behaved child and kind. They love each other deeply and this is the story of their relationship and how it evolves. very cute with some (kinda cliché) hardship.
Edit: oh the betrayal. Was spoiled the end and... I decided to drop while I still have good memory of it.

Once again, Hero-sama and his party saved the beautiful princess from the demon king! As a reward, he asked for a mariage with... The maid? Enjoying her simple role of "maid A". Now everyone try to push her in hero arms, afraid of the retribution if she refused him, while ignorant girls envy her.

Has potential! MC's not your naive shoujo girl and can see through bullshit ! Mmh ML isn't exactly a yandere, his circumstances are quite unfortunate if you think back. Though don't force MC oki?

A girl died and was reincarned in a fantasy world where she became the royale maid. One day a really strong magician asked her to be the mother for a little girl with monstrous power he adopted. And thus started the story of those three.

MC is a mature human and a good mother, the little girl is very cute and nice, the magician is socially awkward but is a good person. A respectful shoujo about how to be a family without blood ties and without the parents being a couple.

Story about a girl who fall in another world. She was taken in by a kind lady but commoners don't have bathtubs. The clean-freak (in denial) with an inexpressive face girl jumped on the first occasion toward her dreamed bath: The king is looking for a side counsort.

If you like shoujo with a not to naive heroine, this is for you!

MC reincarnated as a werewolf magician and is now the leader of one of the Maou troop.
He was entrusted to capture and manage a remote city.

As a former human and now a beast, he can understand all party and is thus consider a wise men. He now has to control his monster troop violence and the ever complaining human.
Promising manga but apparently changed author? http://www.mangago.me/read-manga/jinrou_e_no_tensei_maou_no_fukkan_hajimari_no_shou/

Seems changed author (old version http://www.mangago.me/read-manga/jinrou_e_no_tensei_maou_no_fukukan/). Seems promising.
Mc leads a cute troop of dogs and werewolf. Though powerfull he uses his brain to get minimum casualties on both side.

Mc reincarnated has a werewolf and is a vice-commander of the Maou army. His mission this time is too conquer a remote city.

Free spirit accessories game lover MC was a Top player and the Guild Master of the greatest guild. He quit for 2 years before coming back founding his gold and items hacked, including an unique item, making half of the game inaccessible and everybody hating him for that.
Oh well no stress, let's find/ create the most interesting items as before.