Short answers, pulled from the story.
Martin Luther was the first reformer, sharing his views publicly in 1517. Andreas Karlstadt and Philip Melanchthon joined him almost immediately at Wittenberg, forming the movement's earliest intellectual circle.
Huldrych Zwingli became the first reformer to express a form of the Reformed tradition in 1519, working from Zurich independently of Luther.
The Reformation produced several distinct movements: Lutheran, Reformed, Anglican, Radical (including Anabaptist and Schwenkfelder), and Unitarian. Some reformers influenced multiple movements and are associated with more than one tradition.
Notable precursors included John Wycliffe, Jan Hus, Peter Waldo, Lorenzo Valla, Girolamo Savonarola, and Jacques Lefevre d'Etaples, among others. According to Edmund Hamer Broadbent, these figures and movements sought a return to Apostolic church purity throughout the Middle Ages and foreshadowed Protestant ideas.
Key Counter-Reformers included Ignatius of Loyola, who founded the Jesuits; Pope Paul III, who convened the Council of Trent in 1545; Thomas More; Johann Eck; and Francis Xavier. Pope Leo X was the reigning pope when Luther went public in 1517.
The Second Front Reformers - including Conrad Grebel, Hans Denck, and Balthasar Hubmaier - initially cooperated with the Radical Reformers but separated from them principally in objection to sacralism, the idea of fusing church and state. They are distinguished in the historical record from the mainstream Anabaptist movement.