The life of a Kappa is never dull, especially with such a fantastic family and set of friends! Hana Kappa is young and eager to control what type of flower blooms on his head, but hasn't gotten the hang of it yet. Under his grandfather's tutelage and alongside companions such as Teru Teru Bouzu and Sugiru-kun, Hana Kappa will have plenty of fun and keep his flower safe from the clutches of the nefarious Gaizou and other evildoers in the process!
Coji-Coji feels more adult (in a way) and slapstick and is overall better, but something about the combination of strange spirits (Teru Teru Bouzu for example are in both) and youkai/monsters, plus comedy I think makes these a good fit with each other.
When Maa was just a baby, his spaceship crash-landed in front of Grosser-sensei, and the kind monster decided to raise the child as his own. Now older and attending his adopted parent's school alongside friends such Sebu and rivals such as Bal, Maa can't help but think of his real parents and where they might be in the galaxy. Together with his loved ones, Maa sets forth on an adventure to discover the truth about his mother and father.
Hana Kappa and Ultraman Kids aren't totally similar in genre, but both are kid friendly titles that follow a group of children on a variety of adventures. I think fans of one would probably appreciate the other.