There are lot of jailbreak tools are available for iPhone but some of them are popular such as
- sn0wbreeze
- p0sixspwn,
- redsn0w,
- Absinth,
- evasi0n,
- evasi0n7,
- Pangu.
if you want to jailbreak your iPhone ,You should know following basic things and check it before jailbreaking
- iOS firmware version
- Select the Jailbreak tool for relevant above firmware