Why do all tutorials that use QSVM from qiskit Aqua library have the number of features equal to 2?
Here is a tutorial that uses three classes! If you want to use more than two classes, you need a
multiclass_extension which is provided as a parameter to the QSVM
svm = QSVM(feature_map, training_input, test_input, total_array, multiclass_extension=AllPairs(_QSVM_Estimator, [feature_map]))
As shown in the tutorial. There are a few multiclass extensions to choose from, which are all here.