how to display the list of all monomials occurring in a polynomial

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let $f=x+y+z+xy$, how to display the list of all monomials occuring in $f^2$, by hand computing, the list should be $[x^2y^2;x^2y;xy^2;xyz;x^2;xy ;y^2;xz;yz ;z^2]$

R.<x,y,z>=ZZ[]
f=x+y+z+x*y;f^2