There are and were a very large number of republics in the world. A republican form of government can be combined with many different kinds of political and economic systems, from dictatorship to democracy and from a market economy to a planned economy. Some examples for certain forms of republic are:
Antiquity
Middle Ages and Renaissance
Enlightenment and later
Unitary republics
Unitary republics are
unitary states which are governed constitutionally as one single unit, with a single constitutionally created legislature.
Federal republics
Federal republics are
federal states in which the
administrative divisions (states or provinces) retain a degree of autonomy which is constitutionally protected, and cannot be revoked unilaterally by the national government.
Confederal republics
Confederal republics are associations of sovereign states, usually having power over critical common issues such as
defence and
foreign affairs:
Republics governed in accordance with Islamic law:
These are republics which use the word "democratic" in their official name. Their actual political systems can be very different, and some are arguably not democratic at all.
These are republics which use the word "socialist" in their official name. Their actual economic systems can be very different, and some are arguably not socialist at all.
Meant to be governed by the people, this name is most often (but not always) used by
communist states.
Former People's Republics:
Republicanism
共和国 | 共和国