Schunk and PHD both make adaptors with shanks to put their standard pneumatic gripper modules in a tool holder, and actuate them with TSC or through-spindle air. Combine it with a tray of parts and a pneumatic vise (also from Schunk), and you basically do what a big, complex, external robot does at a literal fraction of the price. Robot or Gripper, you need a pneumatic vise for either system - but the gripper only costs about $1000 all-in (holder, adapter, gripper).
This is a gripper running on a Spedio R650:
To me, this is the missing link between "I don't automate anything" and going on the arduous and $50k journey of part automation with external robots. Schunk even has a new aluminum body KSP vise for $2000, so you can start doing this in a couple of days for ~$3000 in any machine with through coolant or air.
Like any automation solution, it has strengths and weaknesses, but the cost and simplicity make it ideal for an extremely wide range of parts. I'm implementing it on my machine, but there are dozens of shops doing this with fantastic success.
Spindle grippers are the best kept secret in machining.