Haven't played Blockland in some time but whatever.
Basically, playertypes for the various Walker Machines of Xabungle fame. For those who don't know, they're gasoline-powered digger/combat robot combos, usually driven akin to cars by a medley of rough-and-tumble folk known as Civilians and their various subclasses. There are a variety of types, with many mounting turrets or having multiple seats, pretty much all of those things are capable of being done on playertype datablocks, right down to how WMs tend to jump! You can see this in the form of the default Boat, Cannon, and other add-ons, such as Kaje's old Mecha.
The only WMs I'd think would be difficult to make would be the Combat Mecha (except for the Blockary) and Iron Gear, respectively, due to their transformations and how the Iron Gear is loving huge. The Government type WM could have two versions, a regular version and one with the Innocent logo and additional health.
Here are some examples, namely the Dugger, Legg, and Promeus.
Most Walker Machines would simply be fuel jet or jump jet players, with the Doran being the only full jet player since it flies.
I know Bushido at least is a Xabungle fan. Knowing how he built a Gallop a while ago, I find myself wondering why he never decided to make a playertype out of it to boot. If nothing else, the smaller WMs would probably be easy to make, namely the TRAD 11, Gallop, Crab, Legg, Phog, and Burun.