You show to somebody a page for 5 seconds and then ask them several questions. This way you can test if your design communicates effectively the intended message.
Where to use: Marketing and e-commerce websites
You show someone a set of images and ask them which one they prefer. Once they make a choice you ask them a few questions about their choice and try to investigate the why.
Where to use: Fine-tune visual assets, marketing copy, branding and more
This is just a survey where your users go through a sequence of questions and select or type their answers.
Where to use: This type of test is pretty abstract so it can be used for almost everything that can be tested through a survey.
First-click test and navigation test
You show an image to your users and ask them to look for something in the screen. Once they click somewhere either the test is finished or a new screen shows up in case they have to go deeper to find what they are looking for.
Once they are done and you can check if they clicked on the right spots. This is pretty useful to test your content discoverability and your app navigation.
Where to use: Websites and apps