Lasso Selection is a new method of selection that was introduced in AutoCAD 2018. It is an improvement over the previous methods of selection, such as the Polygonal Lasso and Magnetic Lasso.
To use the Lasso Selection method, you first need to select one or more entities on the drawing. Then, you click on Edit > Select > Lasso Selection from the menu bar. You can then lasso-select additional entities by clicking on them.