You're asking for the symbols of elements that are classified as metalloids. Here they are:

* Boron (B)

* Silicon (Si)

* Germanium (Ge)

* Arsenic (As)

* Antimony (Sb)

* Tellurium (Te)

* Polonium (Po)

Some sources also include Astatine (At) as a metalloid, but its classification is debated.