There are different efficient ways to research the potentially best money transfer platforms. The best to do so is to use one of the money transfer comparison tools. They work quite simple. You type in the amount you'd wish to transfer. Fill in what currencies the transfer involve and what is the recipient's country. Hit "compare" and the algorithm will automatically and almost instantly compare your transfer details at all of the available remittance platforms. You will see a list sorted by the costs. Then, you can either simply pick up the top results if you are looking for the cheapest platform, or take a manual research from there and sort the list based on other features such as transaction speed, safety and reliability of the platform, customers' satisfaction, etc.
The offer is very extensive. There are companies focused on providing domestic transfers in certain regions, there are companies operating worldwide, there are platforms which focus on fast transfers, while other take some time yet offer the transactions at the fraction of the costs. You need to figure out yourself, which features are important to you.
It's best to read some reviews and learn about the first-hand experience before making any decision.
For example here you can read a good TransferWise Review. TransferWise is one of the leading international transfers platforms and it's good that the author of the review covers both strong and weak sides of the company. That way you know which features do they offer, but also what drawbacks to expect.
Remember that exchange rates are equally important as the transaction cost itself, as what's the point of cheap transfer if all of the fees are hidden in the currency conversion rates. A bad exchange rate can make an international transfer very expensive very quickly. Always check the rates before ordering the transaction and compare them simply with the ones available for example on Google. That's a quick tip that can save you some money.