Yes, all Osmo Bases include reflectors.
However, you may need to purchase an extra reflector (Osmo Reflector for iPad 2021), if you have one of the newer thin bezel iPad models. Also, you may need a reflector adapter if you have one of the newer Amazon Fire tablet models.
If you are purchasing an Osmo Starter Kit, you will be prompted to add a newer iPad reflector or a Fire reflector adapter for one of the newer models.
For more information, please see this complete list of Osmo-compatible devices.