I don't know too much about post-1998 Joes but was curious about the rarest and most popular variants from 2000 to the present. Thanks.

There is a peg chested varient of the 2000 Undertow figure. This always made me curious because I cannot figure out how the equipment works if you have the other version. There are also versions of Heavy Duty and Alpine with lighter skin tones vs darker skin tones and a whole bunch of slight paint variations in figures (Comic Pack CC, Swamprat, etc...)

There is a peg chested varient of the 2000 Undertow figure. This always made me curious because I cannot figure out how the equipment works if you have the other version. There are also versions of Heavy Duty and Alpine with lighter skin tones vs darker skin tones and a whole bunch of slight paint variations in figures (Comic Pack CC, Swamprat, etc...)
Is the peg version the variant, or is the hole the variant? Just by dumb luck I ended up with one of each, but I always assumed that the hole was the variant, & that at one point there was a plan to attach a hose to the peg.

The '00 Undertow with peg was released first. For whatever reason, the peg was missing and there was just a hole on the later releases. My estimation is that the version with the peg is harder to find, but not by a great deal.

If you have version with the hole, you can squeeze the tube that connects to his mask into it. It takes a little finagaling, but you can do it.