If you're looking for manga similar to 40meterP: Do Re Mi Fa Rondo, you might like these titles.
Hachune Miku is the small and spirited spin-off character of the famous Hatsune Miku. Equally recognizable by her long pigtails and affiliation with leeks, Hachune Miku and her friends go on their own adventures.
Oh no! Milk has disappeared through a mysterious door and only Cinnamoroll can save him! Will he find the courage to help his friend and still make it back to Café Cinnamon in time for tea?
This is the (imaginary) beginning story of the crazy popular Vocaloid Character GUMI!! By some freak incident, the now cyborg school girl has her eyes set on her idol debut as "Gumi" under the mysterious organization, "Intane Group"!?
The manga follows the daily life of a household that has two cats: Azuki and Daizu. Azuki and Daizu belong to an office worker in her 30s who loves cats. The owner lives with her father, mother, grandfather, and older brother, the latter of whom the cats call "Megane" (Glasses). Megane adopted a Shiba Inu dog named Mamenosuke after Mamenosuke's owner died. Mamenosuke grew up around cats so he actually thinks of himself as a cat.
Wansa-kun, is a puppy who was sold for pittance and escapes. He spends the series searching for his mother.