The OFAC list is like a major river that results from a watershed. There are a number of federal laws that generate lists of individuals, companies and countries that are subject to sanctions. Those are all streams flowing into the OFAC river. As Anon 357811 indicated, which stream they came from only becomes relevant when you get a hit. Then, you trace it back to its source and figure out what to do.
As for which of those contributing lists you must check, the answer is: None. Checking the OFAC list is risk based; you do it because the cost of checking is miniscule compared to the potential penalties for dealing with a listed party.
As Anon 357824 said, there are bunches of other lists that are of varying importance that have nothing to do with OFAC. Reviewing them is also a risk based decision.
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In this world you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant.