Hiraheishi wa Kako wo Yumemiru
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.
Sayounara Ryuusei, Konnichiwa Jinsei
A strong dragon let the Heroes party kill him, feeling he lived long enough. But was surprised to be reborn has a human. He will now start his new life as a farmer son with the soul of an ancient dragon. Interesting base... but nothing new. Mc is op thanks to his dragon soul nature and memories. He’s a very calm old soul in a young adult body. Classical OP Isekai. Not bad either.
Jaryuu Tensei
Killed by car because of a stupid couple making out, MC reincarned as a Funny and powerful dragon. He is now leaving in the forest protecting slimes. That story sold me dreams before crushing them... The selling point was that he was a dragon in a RPG like world. But After changing to a human forms, this manga lost what makes it different. It is now a classical Isekai with an MC with OP power (since he is still a dragon inside). I hope he will switch back to his true form.
Maken no Daydreamer
College student died and was reborn as a strong sucubus' son (well that's not exactly it but it will be explained). Leaving in the wildness and training with only his mother and her beasts, she send him on an adventure after he became an adult. To see the world and discover his role in it. His mother was OP, he is OP too.
Ascendance of a Bookworm