A Zero Insertion Force (ZIF) socket is ideal for programming as it does not place any stress on the target IC’s pins. The ZIF socket itself has a regular DIP pinout making it easy to retrofit onto any circuit board.
The only size available currently is the 28-pin ZIF socket. They are particularly useful for programming the Arduino microcontrollers (ATmega 328 and similar). It is also obviously able to program any DIP packages with fewer pins.