I'd love for leaf insects to be tameable as many people irl keep them as pets! I'd also love to see more types of arthropods like jumping spiders or rhinoceros beetles.

• Also I have a question, are there any plans for the mobs that currently don't have any function to get some in the future?

As far as I know, we have no current plans to add tameable leaf insects. Still, version 1.1.0 introduces many new behaviors and functions for the current mobs!
I'll close this for now.