The invention provides single-chain Alphabody library comprising at least 100 different-sequence single-chain Alphabody polypeptides, wherein said Alphabody polypeptides differ from each other in at least one of a defined set of 5 to 20 variegated amino acid residue positions, and wherein at least 70% but not all of said variegated amino acid residue positions are located either in the loop, helix surface or linker region of the Alphabody. The invention further provides methods for use of the Alphabody libraries and Alphabodies obtainable by the methods of the invention.