If you liked the Letter Bee TV anime, the Anime-Planet community thinks you'd like:
Teito Klein is a former slave who attends the Barsburg Empire's military academy. Having no memory of his past and the power to wield a rare ability called Zaiphon, Teito is constantly under the scrutiny of his peers - except for his best friend Mikage, the only person he connects with. After seeing and remembering the man who killed his father, Teito tries to kill him and finds himself on the run from Barsburg's military might. Now, with the evil beings known as Kor after his soul, the Barsburg Empire after his blood and only the legendary Seven Ghosts to protect him, Teito must unlock the memories of his past before he ends up as a sacrifice for Verloren, the sealed God of Death.
Both series are about a boy with powers he is still trying to understand. They are both set in fantastical worlds with their own religion and government, and the main character has to find his way in the world. Both show the friendships and connections necessary in order to make it in the world, and both mix adventure and drama with humor to make an entertaining mix.
In the present day, terrorism is on the rise and the Ua Virus – a biological agent with a 100% kill rate – has been unleashed into the populace. In Shanghai, Canaan is a near-unstoppable soldier who roams the streets, always in the path of a bullet. She is a Synesthetist – a person able to use all five senses at once – who harbors a burning desire for revenge and has a past shrouded in mystery. While the Ua Virus infects more people in the city, others cross paths with Canaan including Minoru, a freelance journalist; Maria, Canaan’s close friend who was infected with the Ua Virus and lost her memory of the incident; and The Snakes, a shady and violent group with mysterious motives. Danger lies at every turn for Canaan and ultimately the rest of mankind…
Both series are about a person who has special powers and uses a gun to protect the people they love. The visuals in both anime are beautiful, although Canann is more on the adult side, they are both really good.
The cheery Kobato Hanato is on a mission to heal people’s damaged hearts and gather the resulting “konpeito”; she must collect one hundred of these candy-shaped trophies in order for her deepest wish to be granted: to go to a certain place. Along the way, she’s accompanied by an ever-disgruntled, talking stuffed animal of a guardian named Ioryogi who scores her efforts, attempts to keep her on-track, and reminds her of the rules governing her task: she only has one year to fulfill her goal and she must not, under any circumstance, fall in love with someone whose heart she heals.
Both of these series are kind of centered around "the heart," be it delivering the heart or mending it. Also, each of these series leave a lot of questions unanswered for most or all of the series, while the main character kind of just runs around trying to deliver/mend hearts.
To make money, high school student Shinkurou Kurenai works for the secretive Benika as a "dispute mediator," acting to intervene in the disputes of clients – often violently. One day, Benika gives him a much different assignment: to protect Murasaki Kuhoin, a seven-year-old girl from the wealthy Kuhoin family. This turns out to be a more troublesome task than he expects, as Murasaki is spoiled, naive, and completely unaware of what life is like outside of the luxurious one she had previously. He also has no idea why Murasaki needs his protection, though he is slowly obtaining details from a well-informed classmate. Adding to his problems, Shinkurou still must continue to do his previous work for Benika and take care of his social relationships in school while protecting Murasaki, complicating his entire life. Nonetheless, as time passes, he and Murasaki grow close; however, trouble brews in the shadows as everyone - including Shinkurou - seems to be harboring secrets...
Natsume is lonely; he has an ability that separates him from others: he can see and interact with spirits. Soon, however, Natsume discovers that he’s not alone: his grandmother Reiko also had the gift. But things get hectic and possibly dangerous for Natsume when he finds out that he also inherited the 'Book of Friends', a book that contains the names of all the spirits Reiko defeated and subjugated. He finds himself hounded by his grandmother's underlings and, with the help of a 'cat' charm spirit, decides to free them from the Book's shackles, as well as protect the book from those who seek to misuse its power...
While watching Letter Bee I got vibes of Nastume. Both offer a relaxing atmosphere. There is a common theme both share, helping out others. Nastume always helps out the youkai and in Letter Bee, Lag delievers letters to people while showing the heart of their letters.