Standard
1 1/16 straight
1 1/16 Keyhole
13/16 straight
5/8 straight
5/16 straight
BTW - my source is the INSTRUCTION MANUAL - it says what it comes with.
Usually one is stored inside the unit and four in holder in the box
Then there is the box of four (these also came in individual boxes)
3/8 straight
1/2 straight
5/8 Keyhole
15/16 straight
you can also get the Eyelet - (it's got a hole in it to tell it from the 3/8" straight)
I think the plastic cams came in 11 sizes - standard with the buttonholer. I'd have to go back upstairs and count to be sure.
So far, I've not seen any other sizes of the metal cams.
You will find units in all sorts of price ranges on ebay. Best deals are ones that come with several items. People get stupid and will by $20 three times for three items, but won't pay $40 once for the same three items in one lot.
AND - don't get sucked into the "Fits a FW" marketing hype. All low shank ones fit the FW - but if the sellers says "FW" in the add, often buyers who don't know better will pay more. I don't know if the black cases were made specifically for the FW machines - but I do know that the unit inside the black case is the same as the unit inside the green case.