The Consolidated Screening List is the most practical starting point for anyone building screening from scratch, because it collapses several separately published lists into one structure.
What it bundles
The OFAC SDN and consolidated non-SDN lists, the Bureau of Industry and Security Entity List, Denied Persons List, Unverified List and Military End User List, and State Department lists, among others.
The trap it does not remove
Bundling the lists into one file does not make the obligations identical. Being on the Entity List imposes a licence requirement on exports; being on the SDN List blocks property and prohibits dealings. A screening system that treats a hit as a hit, without reading which list produced it, will get the consequence wrong in both directions.
Every record in the file carries its source list, and that field is the important one.
Access
There is a public search interface, and an API. The API requires a key, which is free to obtain; the search interface does not.