There are a few different types of list filtering that can be useful in different situations. The most common type is probably the simplest: removing duplicates from a list. This can be done easily with the set() function in Python, which will take a list and return a new set object containing only the unique items from the original list.

Another common type of filtering is finding items in a list that meet certain criteria. For example, you might have a list of numbers and want to find all the even numbers, or you might have a list of strings and want to find all the ones that start with a certain letter. This can be done with the filter() function, which takes a function and a list as arguments and returns a new list containing only the items from the original list that return True when passed to the function.

Finally, you might want to transform the items in a list into something else. For example, you might have a list of strings and want to turn them all into uppercase. This can be done with the map() function, which takes a function and a list as arguments and returns a new list containing the results of calling the function on each item in the original list.