The Bugbear has a trait called Long-Limbed that states:
When you make a melee attack on your turn, your reach for it is 5 feet greater than normal.
The Way of the Astral Self monk has a feature called Arms of the Astral Self that gives the monk many benefits, but the ones I want to focus on are:
You can use the spectral arms to make unarmed strikes. When you make an unarmed strike with the arms on your turn, your reach for it is 5 feet greater than normal.
Do the reach increases from Long-Limbed and Arms of the Astral Self stack?