Well there's been Carberry recently in the test side. Then there's Phil DeFreitas, Devon Malcolm, Gladstone Small etc.
Sid Lawrence, the late Wilf Slack, Norman Cowans, the imprisoned Chris Lewis, Ricky Elcock and so on but the numbers over the years probably aren't huge.
I can't say too much about what the case is in today's county game, tbh, as I hardly follow it.
Theres not that many playing county cricket. Keith Barker at Warwickshire but cricket is his second choice because he was on Blackburn's books i think. Guess its not a sport too many young black people are that interested in taking up. A bigger question is the lack of asian cricketers playing for England or even playing county cricket when it is a sport they participate in at young age. Still not totally sure why Moeen Ali left Warwickshire seven years ago to play for Worcestershire. He said it was the time he becoming a fully fledged muslim and he wanted to start afresh where nobody knew him without a long beard. Certainly if he had have been at Warwickshire he would not have had to wait until he was 26 to play for England.