From a quick look at the squad contracts it seems all of these players are out of contract in June 2022.

Smithies
Morrison
Flint
Vaulks
Ralls
Pack
Murphy
Tomlin

Personally I would not be too gutted to see most of them go. It gives a very real chance to overhaul the midfield here for one.
Some of them listed just don't seem bothered to play and when they do seem unmotivated and there are also some aging players in that lot that simply need replacing by younger models.

Who would you let go, who would you keep and why?
Whether MM is the man to make the signings/spend the money to replace them is another argument too.