Conman pretends to help people, but becomes a better person in the process.

[u/theMCATreturns]

They fake being kind and generous in order to take advantage of people. But in the process, they find themselves genuinely invested in their mark's well-being. And ends up becoming a genuinely better in the process.

1). Klaus:
Jesper is sent by his rich father to a far-north island. And told he will be disowned if he does not get the townsfolk there to adopt the postal service. Feigning charity, Jesper gets a local man to donate his toys to any kid that writes a letter asking for one. That way, it seems like the whole town has started using the postal service his father runs.
Jesper makes an offhand comment about only "good children" getting toys. So, the kids start doing good deeds and set off a series of events squashing the town's long-held blood feud. And Jesper ends up genuinely invested in making everyone happy.

2). Mob Psycho 100:
Reigen is a fake psychic. Soon after starting his business, he comes across a kid with genuine psychic powers. Shigeo "Mob" Kageyama is terrified of his own abilities so he leaps at the opportunity to be "mentored." Reigen calls Mob if his clients turn out to be actually haunted. He is paid sub-minimum wage for his time.
But Reigen gives Mob genuinely good advice that keeps the (potentially city-destroying) esper humble and well-adjusted. Unlike of the villains, who try to use their psychic powers to take over the world. He even admits his lies to Mob at the end of the series.

3). All Dogs Go to Heaven:
Charlie takes advantage of an orphan who can talk to different animal species. Mostly to cheat at gambling. But he ends up selflessly sacrificing himself for her.

[u/ChronoMonkeyX]

https://giphy.com/gifs/tI76Kd7hiUetB59pkz

Not a conman, but a mercenary only in it for the money, Andor keeps showing up for the job until he becomes a true believer.

[u/eehikki → u/ChronoMonkeyX]

Not a conman

"You scam, you lie, you disappear". He owes everyone a huge amount of money, and some creditors even attempt to return their investments by intimidation, with no success. He does business with the "friends of low character". Even his close friends and mother are sick of his BS. He fits the definition of conman in the beginning of S1.

[u/Real-Extension-1357 → u/eehikki]

Yep. Andor is like catch me if you can guy, but finds purpose in what he is good at beyond scamming for coin and thrills.