If you're looking for anime similar to Ketsuekigata-kun! 3, you might like these titles.
It is a story of Untaro the poop. One day, he ventures out into the outside world. He experiences various things and grows up to be a fertilizer.
Tired of repeating the same task (cell division) day after day, the Normal Cell laments while working his boring job, when a mysterious cell wearing a charming hat suddenly appears in front of him. This cell proceeds to invite the Normal Cell to spread mischief and play pranks on the White Blood Cells (Neutrophils) and Killer T Cells. Though the Normal Cell enjoys being able to blow off some steam from his day to day life, who is this charming hat wearing cell?
The anime center on vegetables that children hate, everyone hesitates to eat, and are smelly. The series follows these vegetables as they visit a bar to share drinks together while they talk about their worries.