Homotopy and homotopy group studies can be used to label the topological defects based on their topological invariant properties (the labels are usually associated with these). In some cases, they are called "charge", and indeed they can be realized as charged in some sense (for example, in cases of vortices in a 2D XY model, opposite charge vortices are attracted while same ones repelled)
Spherical order parameter space's homotopy groups can be easily read-off from the following tables:
