I used to make several barrel handler clamps for steel drums. they are pretty simple just need enough contact area around the rim to keep them from slipping then lift from the middle and off you go
Plastic drums can be carried the same way but you should have a lot more contact area.
Here is what I came up with
I really do need to take the time someday to make a froge
the bits fit together ready for welding
Works perfectly even on a drum with the head removed