I have my first draft of a big board put together. The top of this class is really tough and I'm sure Ill have some changes in opinion when I get a chance to watch more games. I did break the board up into rough tier groups. 
    Player   Team
1   Ron Holland   G-League
2   Nikola Topic   Int
3   Alex Sarr   Int
      
4   Stephon Castle   Uconn
5   Donovan Clingan   Uconn
6   Zaccharie Risacher   Int
7   Matas Buzelis   G-League
8   Cody Williams   Colorado
      
9   Kel'el Ware   Indiana
10   Reed Sheppard   UK
11   Rob Dillingham   UK
12   Isaiah Collier   USC
13   Tyler Smith   G-League
14   Ja'Kobe Walter   Baylor
      
15   Yves Missi   Baylor
16   Melvin Ajinca   Int
17   Harrison Ingram   UNC
18   John Furphy   Kansas
19   Kyle Filipowski   Duke
20   Zach Edey   Purdue
21   Adem Bona   UCLA
22   Izan Almansa   G-League
      
23   Dalton Knecht   Tennessee
24   Tidjane Salaun   Int
25   Jared McCain   Duke
26   Terrance Shannon   Illinois
      
27   Daron Holmes   Dayton
28   Bobi Klintman   Int
29   Ryan Dunn   Virginia
30   Trey Alexander   Creighton
A few observations.
Holland is underrated on alot of the main stream boards, I see alot of similarities with Jaylen Brown
Kel'el Ware like most bigs is a gamble because they historically develop slowly but I can't see him not being worth a lottery pick.
Both UK guards Sheppard and Dillingham scare me, neither has the desired positional size for PGs let along combo guards. The last draft saw a major trend away from smaller guards.
Missi, I am not sold that he is worlds ahead of Bona. He is longer but Bona looks like the more explosive athlete.
Melvin Ajinca, he is being under valued. Has good size, is athletic, can shoot the 3, and was very productive in FIBA.
Izan Almansa, great touch for a 18yr old. Struggled in G-League but was MVP of FIBA U19