What colleges are in tier 1, tier 2, and tier 3?

You could sort colleges by rough selectivity if you would like:

https://amp.businessinsider.com/the-610-smartest-colleges-in-america-2015-9

https://www.businessinsider.com/the-50-smartest-colleges-in-america-2016-10

The value, however, of analyses such as these resides mostly in their inclusion of a wide range of schools, including those that may not previously have been familiar to you.