<p>I know of: Harvard, Yale, Stanford, Dartmouth. HYS each send out around 100, and I think Dartmouth sends out about 400.</p>
<p>Also, you need to distinguish between athletic and non-athletic likely letters, which are at different times of the admissions cycle, typically. The “coveted” ones (as it were, at least on CC) are those in the RD round.</p>