What were the different types of governments during the Renaissance to 1650 AD?

Answer 1

Most European nations were a monarchy.

The Papal States could be considered a theocracy (ruled by the Pope), although in reality, it was usually ruled like any other monarchy.

Venice, Genoa, and the Dutch Republic were republics.

Poland-Lithuania was a commonwealth (more precisely, a semi-federal, semi-confederal aristocratic republic)

The Holy Roman Empire was, during the Renaissance, a very loose federal monarchy (especially after the Peace of Westphalia in 1648).