Zenryoku Usagi

both are half-length episodes aimed kids anime that have adult themes such as working, caring for family and etc. Zenryoku Usagi is more comedic while Rilakkuma is more slice of life-ish and Rilakkuma have more diverse themes despite being shorter and Zenryoku Usagi is really more focused on working 

both are kids shows feature humanoid rabbit main cast (Happy Happy Clover have other animals too but Zenryoku Usagi only have rabbits) that teach the kids several lessons in a fun way Zenryoku Usagi is quite focused on "work" theme and also some of the episodes of Happy Happy Clover are the same 

Talking animals in the workplace, ZU about rabbits within construction whereas RA being about a ramen shop. We see the everyday life and activities of both sides tho a main difference is that ZU is just rabbits whereas RA has cats and humans living together. 

Different settings and different pathways, both shows talk about apprentices growing to become fully fledged in their area of expertise. Both shows are aimed towards children and so are very cute and fun to watch as you see how they grow with each episode. Both do have their moments of drama at times but only so that the characters can grow but all in all very heart-warming to watch. Both shows also have Kotono Mitsuishi playing as an older sister-like figure, although appears more in Usagi compared to Sugar. 

Damekko Doubutsu and Zenryoku Usagi are both kids' anime, with episodes less than ten minutes long. They share many of the same humorous points, too: both have comically useless protagonists who are always getting picked on by more confident (if no less odd) supporting characters, both contain just a tidbit of drama to even out the comedy, and of course, both feature cute animals. Anyone who liked one will probably enjoy the other.