Schutzhund Malinois are found predominantly in Germany, the Czech and Slovak Republics. The #1 line for these dogs undoubtedly, comes from Klemm Roten Falken. He is long dead, but dogs going back to him dominant the sport. These lines, preceding Klemm go back to foundational dogs from Belgium and France.
In America, Ivan Balabanov has a successful IGP Malinois breeding program going back to his 3 time world champion. There are many other successful SchH Malinois breeders, but no one has his bona fides behind them.