There is no exact Vce value that can be called a standard or reference saturation voltage. It differs from transistor to transistor. Even for the same transistor, it will vary with the collector current level and with temperature.
For example, one particular type may have a Vce(sat) of 0.2V at a collector current of 50mA and 0.35V at 100mA. Another transistor may have a Vce(sat) of 0.1V at 50mA and 0.15V at 100mA.
It also varies slightly with the amount of Ib being forced into the base, which is why Vce(sat) is always specified in datasheets for a given Ic/Ib ratio. The specified ratio is usually 10 but may be 20 for high-beta transistors, and lower than 10 for low-beta power transistors.