One of the more interesting picks by the Pittsburgh Pirates on day three of the draft was Jack Herman, a high school outfielder from NJ taken in the 30th round. Here's his player page. Herman told the local media that he will sign on June 18th and that the Pirates will pay for his college, which is standard for all high school players signed, and doesn't count against the bonus pool.
https://twitter.com/PhilAnastasia/status/1004866981143764997
As for other prep players, 22nd round pick Jason Brandow, has said that he is still deciding between signing and attending Cal State Fullerton.
Giovanni DiGiacomo (29th round) has said he will attend LSU.