Energy development

Are there any other major sources of renewable energy apart from solar energy, hydro electric power and wind energy?

There are. Biomass, Biofuels, vegetable oil...

These forms of renewable energy are not invest worthy so they are not used as much. but they are used most often in rural areas.

Yes bio gas, waste energy plant etc

Wave power isn't quite hydroelectric. Burning wood chips is renewable because trees regrow. Geothermal, or hot rocks, is another source of energy that is renewed all the time from magma deep in the earth's crust. This energy comes from the radioactive decay of Uranium, Thorium and other radio active isotopes in the Earth's mantle and will last billions of years.