Baseball Prospect released their mid-season list of the top 50 prospects and they have four Pittsburgh Pirates, with another one that includes as asterisk. They have Tyler Glasnow ranked #17, followed by Reese McGuire at #29, Josh Bell at #33 and Austin Meadows at #46.
There is also the case of Jameson Taillon, who they noted would have been somewhere in the teens, but they left him off due to the uncertainty of his latest injury. They didn't say the injury hurts his prospect status, rather the timing of it and the unknown success/recovery time makes it impossible to rank him at this point.