The decision on what filter to use when shooting landscapes can always be a tough one. There are so many and each one has their own use. To name just a few:

• Polarizer: which cuts down glare
• Circular polarizer: which lets you dial in how much glare is cut down
• Neutral Density: darkens the exposure
• Circular Neutral Density: lets you dial in how much of the exposure is cut down
• Graduated ND: A Neutral Density filter that has one side very dark and the other side very light . One goes to the other very gradually and it’s typically used to cut down the effects of a harsh sky.
• UV filter: cuts down UV glare and protects the front element

These are just a few to name, but the video below not only names a load of filters but also shows you their effects when it comes to landscape photography and seascape photography. Each of them lets you create your own creative effect and though the speaker uses aperture priority, you can get much different results when using manual mode because then you have a total 100% control over the image.