Are you looking for a list of international couriers? While there isn’t really a list of couriers to go by per se, you can always look online to find a courier that sends internationally near you.
Price and deliver ability to your location of choice really depends on where you need to send off to. This means that not all couriers will be able to quote you the same price whilst providing the same service. Its just not possible.
You also have to keep in mind that some countries are stricter than others in allowing certain items. Any sort of liquid you may be looking to send, unless it is water, might be restricted since many liquid compounds can easily be corrosive (acidic) which can detriment an entire shipment of packages. This means that because of your package an entire shipment gets ruined and no courier can afford to let this happen.
Books are probably the most common and safest option to ship. They also happen to be the cheapest as well. As long as you can prove your package is a book you can easily ship it to almost any country accepting mail. The problems just come for borderline substances like liquids which can easily lead to hazards for other packages in a given shipment.