In all my time gaming, reading, writing, and thinking I have come across all kinds of people who's sight isn't limited by what their eyes can see and here I will be naming and describing each class.
A Breakdown of Seers
I will be defining Seer by: One who influences or is directly influenced by the timeline.
Past
Viewers- Can see the events of the past. (Because the past is already set. Someone with this gift can see farther and more clearly than those that see the future. Viewers are also known as Librarians or Historians due to their intimate knowledge of the past.)
Present
Watcher- Can see the past, present, or future events, but only within a limited timeframe. (The abilities of a Watcher most commonly develop their abilities due to a near death encounter and usually only give hints about to happens a split second before it does, but those who are born with it are able to see more than 24 hours and only the most powerful can see beyond 36 hours.)
Diviner- Someone who uses crystal balls, animal bones, or similar items to see other times or locations. (A Diviner is very similar to a Watcher; they can see farther, but require a focus)
Future
Psychic- One who can see the future. (Further broken down into four subcategories.)
Soothsayer- Someone who reads the positive and negative energies surrounding to guess short-term impacts regarding the one consulting them. (While not reliable for determining ones fate, but consulting one is useful to determine short-term impacts of a decision.)
Sibyl- An individual that is able to be used as a medium for a powerful force or entity to speak of a possible future. (Linked to to bloodlines, and unable to recall if a prophecy is spoken through them.)
Prophet- A medium similar to a Sibyl, but trained to reach out to reach out to their chosen force or entity. (Tied to a faith or religion, and usually has to reach out to receive a prophecy.)
Oracle- A person gifted by fate at birth to receive visions of a future that will come to pass. (An oracle's vision will come to pass and can not be circumvented or avoided no matter what actions taken to prevent it.)
Other
Gazer- A very special and rare type of seer that doesn't see through time, but through the veil that separates timelines. (Most Gazers can only see into timelines that split off around the time of their birth, but some very powerful ones are able to view the whole multiverse even if only for a short amount of time.)
Chosen Ones- A special type of seer that is not gifted with any kind of sight or knowledge, but is instead given limited freedom from fate. (In return for such freedom they are tasked with creating the best possible future and in some cases even changing the past and actions of another Chosen One to bring it about. Freedom from fate comes at the price of a life of danger, strife, and responsibility. The birth or arrival of a chosen one is almost always foretold by an Oracle.)