Given the fact Konami has put Vol. 1 on the end of its Metal Gear Solid: Master Collection, it seems incredibly likely there'll be a Vol. 2 in the future. However, no official confirmation has been shared at the time of writing. There are rumours, though, which point to a second collection containing Metal Gear Solid 4: Guns of the Patriots, Metal Gear Solid V: The Phantom Pain (presumably with Ground Zeroes bundled in), and Metal Gear Solid Peace Walker.
Speaking generally, some of the possibilities for Vol. 2 are:
Metal Gear Solid 4: Guns of the Patriots
Metal Gear Solid V: The Phantom Pain + Ground Zeroes
Metal Gear Solid: Peace Walker
Metal Gear Solid: Portable Ops
Metal Gear Acid
Metal Gear Acid 2
Metal Gear Rising: Revengeance
Metal Gear Survive