Yoda's species is famously shrouded in mystery, and The Mandalorian shows exactly why it's so rare in Star Wars. Very few of its members have appeared in canon, but two of them, Jedi Master Yoda and Mandalorian foundling Grogu, have played major roles in the Star Wars saga. Yaddle, a female member of Yoda's species, had a minor role in Star Wars: Episode I - The Phantom Menace. Though Yaddle's eventual fate is still unknown in the new Disney canon, the species is capable of reaching highly advanced ages. Though Grogu had the looks and mannerisms of a toddler, he is around 50 years old during The Mandalorian. Yoda, who was already a Jedi during the High Republic era, nearly lived to see the fall of the Galactic Empire. He was 900 years old at the time of his death. Each of the three known conspecifics were Force-sensitive and used its related powers skillfully.
Yoda's species is ancient and powerful, but the details of their culture and biology are an enigma. They are few in number and are scattered across the galaxy, shielding themselves from the preening eyes of outsiders. In fact, the species is so secretive that they do not even have a proper canon name. The little green Force-users have long been one of Star Wars' greatest mysteries, and while The Mandalorian has not offered an answer to what exactly they are, it has demonstrated why they seemingly live so privately.
Grogu was endlessly chased by remnants of the Empire throughout the The Mandalorian's first two seasons, a fate that could have easily befallen any child of the same species who ended up exposed. The perseverance of Grogu's pursuers showed that there was something very special about Yoda's species. There were surely other Force-sensitive children of a myriad of species in the galaxy, but Moff Gideon (Giancarlo Esposito) chose to hunt Grogu specifically. Despite being a baby, Grogu exhibited immense Force powers unseen in children of other species, and could already perform telekinesis and Force healing. These powers only made the Imperial officers more relentless. Grogu tried his best to defend himself, but was still subjected to kidnapping and experimentation, proving that he was still vulnerable even with his abilities.
This treatment of Grogu in The Mandalorian suggests that any child of Yoda's species, no matter the era of their birth, could be exploited for nefarious purposes. Dark forces have always existed in the Star Wars universe, creating a constant need to keep the little ones hidden away. Their long infancy means that they would have remained defenseless for decades, and the adults would also presumably need to conceal themselves to raise and protect them.
The Mandalorian did not reveal too much about Yoda's species, and Grogu's departure with Luke Skywalker during the season 2 finale may have disappointed fans hoping to see more of its members. However, Grogu's ongoing popularity - and profitability through merchandise sales - means that they may not have seen the last of him. In addition, there is a myriad of new Star Wars content on the horizon, and any of it could introduce new members of Yoda's species, or even give it a name.
