So far Blue Abashi, Demigorgon, Deurgar, Star Spawn, for monsters.
For playable races Eladarin and Centaurs. Last time I checked Eladarin was a subrace and playable Centaurs so far in 5e have only been in MtG setting books, Ravnica and Theros. This will be the first time Centaurs will published for the regular D&D multiverse. This could mean fresh lore.