What metalloids are malleable?
Apparently none. Malleability is a property of metals, a result of the metallic bonding between atoms of the metal. I suspect it is closely related to ductility, the ability of a substance to be drawn into a wire. I found a table of ductility at this location:
Looking down the list I did not see any metalloids, only metals. I would expect a similar listing of malleability to show results that are almost identical.