In which other countries Electronic items purchased from India can be used without any voltage converter and vice versa?
India has a 230V 50Hz (voltage of 230 Volts, frequency of 50 Hertz) system. Therefore any electronics purchased for a country with this voltage and frequency will obviously work.
However the situation in reality is much better than this. Almost all modern electronics is designed to work with a wide range of AC input voltages and frequencies, because they don't want to make different versions of the device for different countries. Most are designed to take any input from 110-240V and 50-60Hz, which would include the power supplies of India.
To check for any specific device, look on the power supply. It will have (in small letters) a line like:
AC Input:100-240V 50-60Hz.
This specifies a voltage range and a frequency (Hz) range. If the range includes 230V and 50Hz then your device will work in India without an additional voltage converter.
If you haven't yet bought the device you can usually download the manual for it, which will have the same statement somewhere. Or if you are in a store, ask the salesperson to show you the line on the power supply.
You may still require a plug converter, which is very different from a voltage converter and much cheaper. Or if you are bringing the device permanently to India, take off the foreign plug on the cable and attach an Indian one (get an electrician, or a friend who knows what they are doing if you are not sure about how to do this).
Some higher-consumption things like hairdryers have a switch on them that allows them to work with either 110V or 220V. In most of those cases the 220V setting should work with 230V, but read the manual to be sure.