Centaur no Nayami

Both are chill slice of life series that focus on the political aspects of the world if demi's actually existed. Centaur focuses on this aspect more. 

Both are very cute SoL series that feature around Demis (or creatures that resemble humans with mythological features; ie Macchi being a dullahan, and Himeno being a centaur) that react and exist in a normal school as if they belong there. However, unlike Demi-chan, Centaur's humans no longer exist in the world, and the entire school-base is completely demi, while Hikari, Macchi and Yuuki are considered as minorities and outsiders to a majority ruled school of humans. However, while I enjoyed Demi much more, I believe that these two series are very similar, and if you enjoyed one, I'm sure you'll enjoy the other.  

Has demi girls but uses them more effectively and is a nice and enjoyable heart warming show. Also, very funny. Has less actual demis but does have a nicer selection of what demis the MC are. 

Both are animes about daily life. Also both have monsters as main characters 

Both series have cute animal girls doing cute things, having fun with their friends and enjoying life while contemplating the bigger questions of life. 

Both are anime that explore cultures and society of various fantasy races. If you like monster girls, you will likely enjoy these.