Zeikin de Katta Hon
About a young (seemingly delinquent) working as a parttimer in a library. Good Slice of Life, especially recommended for Bookworms ;)
Wakeari Shinrei Mansion
Slice of Life with Life lessons about self improvement, not judging a book by its cover and good communication with others, while still being comedic and lighthearted
Hirayasumi
Wholesome Slice of Life about two cousins living together, overcoming their own life-struggles. Even though the manga gets you emotional sometimes, its still a good everyday read, as its still funny and lighthearted most of the time
Yotsubato!
This manga just gets you rolling on the floor from laughing so much. Highly recommended, if you want to laugh ^^
Star Tripper: Planetarium Ghost Travel
This one is more of calm and melancolic slice of life. One to read late at night
Kimi to Uchuu wo Aruku Tame ni
About learning accept who you are, while still learning to improve yourself. Still a funny and often lighthearted Slice of Life
Assassin no Kyuujitsu
A very funny and wholesome Slice of Life manga
Kingyo Used Books
A Good Slice of Life manga with many Life lessons and bonus points if you love books and/or manga :)
Totsukuni no Shoujo
A Fantasy Manga about being a Family and morals of society
Nan Hao & Shang Feng