If you liked the Usagi Drop anime, the Anime-Planet community thinks you'd like:
Kamba and Shouma Takakura have taken care of their sickly younger sister Himari since their parents disappeared years ago - that is, until the day she died. But as the boys grieve by her hospital bed, Himari sits up, adorned with a strange penguin hat. Suddenly, the three of them are transported to a vibrant world where the hat, using Himari's body as a puppet, charges these brothers with a task: find the Penguin Drum and their sister's life will be saved! Now aided by some odd penguins they received in the mail, the duo must find this mysterious item or risk losing the sister they care for so much. However, they aren't the only ones with their sights on the Penguin Drum, for new enemies await them around every turn, all connected in ways they would have never imagined...
There are many differences that separate Penguindrum and Usagi Drop, so at first this may seem like a strange recommendation, but hear me out.
Penguindrum is full of beautiful imagery, metaphors and has a very distinct visual style that weaves its way into the telling of the story, which at times verges into dark territory. Usagi Drop, on the other hand, is a very straightforward tale of a man raising a child. Usagi Drop's visual style is softer, and it's story is so lighthearted and heartwarming, I guarantee you'll smile while you watch it. Penguindrum is a much more fantastical in its storytelling and themes, while Usagi Drop has nothing of the sort, instead opting for realism. Lastly, it's also important to note that Usagi Drop lacks the bizarre sense of humor Penguindrum has.
Despite these extreme differences between the two, there is one key reason I feel these two shows go together well -- the concept of family. The idea of what it means to be a family and the bonds that connect family members are important themes that resonate throughout both shows. I feel as if you liked the concept in one, you will probably enjoy the other.
Also, both Rin from Usagi Drop and Himari from Penguindrum are super adorable -- both characters' silly antics and cute facial expressions made me giggle and smile while watching. I highly, highly recommend both!
Satsuki, her younger sister Mei and their father have just moved to their new home in the countryside, where grand adventures await them. One day while playing outside in the garden Mei encounters a small creature and decides to follow it. After chasing it through the bushes Mei eventually finds herself at the base of a large Camphor tree and as she drops through a hole in its roots, she lands on the stomach of a large, sleeping forest spirit named Totoro. The two sisters befriend the gentle spirit and are soon introduced to a world more fantastical than they could ever imagine, from playing with soot spirits to meeting a Catbus, to flying through the air and even making the trees grow. However when Mei disappears, Satsuki must call on the help of her new friends if she wants any hope of being able to find her sister...
While they may take place in completely different settings, these two anime remind me of each other. Both Bakumatsu Kikansetsu Irohanihoheto and Le Chevalier D'Eon are based around actual history that have supernatural elements woven into them. These are also both serious anime that can lose a person if you don't pay attention.
Both of these animes has a guy who ends up having to take in children and raise them like their own. They're both very sweet and heartwarming. If you're into slice of life, these two are one's you'll definitely love.