If you're looking for manga similar to Gan Gan Ganko-chan 2nd Season, you might like these titles.
He's small, he's scaly, he's Gon! This tiny dinosaur may seem like nothing but a lazy reptile that lounges around and causes mischief, but he's also a pint-sized powerhouse filled with energy who can defend himself when the right kind of food is involved. Whether he's riding a lion like a horse, stealing fish from the mouth of a giant shark or playing house with a group of penguins, Gon manages to get into trouble on every adventure he takes.
The story follows a little shark character, Kozame-chan's adventures in Yauo town, which smells "nostalgic." From radio exercises to festival stalls to meeting with friends, Kozame-chan has a variety of heartwarming experiences in the town.