Classical liberalism is the political ideology which considers individual liberty can lead to positive results. It speaks about the self-reliance of an individual.
The principle of laissez faire highlights the economic liberalism. It says that the minimal interference of the Government in formulating trade policies would bring developments in trade. Adam Smith is a famous supporter of Laissez Faire.
Negative freedom is another form of liberalism and it can also be denoted as extreme liberalism which states that an individual works better when he stays alone and free without any restrictions. It aims for a civil society wherein individuals are not restrained and they are free to follow their aspirations and which would mold them to be productive.