Mladorossi loosely translates to "Young Russians," and was a pro-tsarist group of émigrés that existed in the years between the Revolution and the Second World War, formed by younger Russians disillusioned with the older exiled nobles. Its founder was Alexander Kazembek, who was later forced out when he was seen meeting with Soviet officials; it was thought they were trying to recruit him, so he left for the US. The group kind of disbanded afterwards.

There isn't a lot on them in English, and the Russian materials I've found are sparse as well, though they seem to have some popularity with some Russian nationalist groups. They had some unusual views, such as the idea that the tsar could lead the Soviet Union, and they supported the October Revolution in that they felt it necessary, but should have been more nationalist and a higher focus on Russians, and not the other groups in the Empire/USSR.