See the chart below for a more detailed description

Fish gelatin powder and agar (also known as agar powder) are good buys.

Also as mentioned upstairs, since QQ candy and marshmallows are both made from the above ingredients, you can get them as well if you use the water heating method. But because they are made with fruit juice concentrate and additives, there will be some limitations in terms of homemade flavors and self-creation ...... so it is recommended to use agar instead. Agar is also relatively easy to buy (since it's for making tofu) and you can find it at the grocery store or sub store. I just bought a bag of it yesterday at the farmer's market near my home - 16 bucks for 260 grams and it will last me a long time.