Blade:     Common tip type for kelvin testing

‍‍‍‍Ladd‍‍er‍‍‍‍‍‍:  Similar with blade type but would be more accurate on positioning

Half moon: Mostly applied in QFN, QFP

Crown:   No need to be aware of the  direction when manufacture the socket and  pin inserting since each claw can perfectly prick on testing area