The Soccerex 20 U21 Report
1. Raheem Sterling (Liverpool) £35m
2. Marquinhos (PSG) £28.3m
3. Memphis Depay (Man Utd) £23.9m
4. Domenico Berardi (Sassuolo, co-owned by Juventus) £21.7m
5. Jose Gimenez (Atletico Madrid) £21.5m
6. Hakan Calhanoglu (Bayer Leverkusen) £19.5m
7. Mateo Kovacic (Inter Milan) £18.6m
8. Jose Luis Gaya (Valencia) £18.4m
9. Luke Shaw (Man Utd) £18m
10. Aymeric Laporte (Athletic Bilbao) £17m
11. Kurt Zouma (Chelsea) £16.2m
12. Youri Tielemans (Anderlecht) £13.8m
13. Alexsandar Mitrovic (Anderlecht) £12.9m
14. Anderson Talisca (Benfica) £12.9m
15. Emre Can (Liverpool) £12.1m
16. John Stones (Everton) £12m
17. Anthony Martial (Monaco) £11.3m
18. Divock Origi (Liverpool) £10.9m
19. Calum Chambers (Arsenal) £10.7m
20. Hector Bellerin (Arsenal) £10.5m
I reckon even Luke Shaw thinks he's been overrated there

Must admit I've not heard of some of these players, such as Berardi, Gimenez &
Calhanoglu .
Some decent young players on there though like Tielemans & Mitrovic at Anderlecht. See a few Prem clubs have been linked with the later this window, the former is still very young but quite experienced.
Belgian league is a decent breeding ground for young players it seems.