I'll run through a few guys, you can't watch everything at practice so I can't say I have a handle on everybody.
Alexander: On the short side but shows a lot of quickness and explosiveness and competitiveness.
Jackson: Good size but very grabby. Probably will need more time to develop than Alexader.
Burks: Interesting player, can run in coverage, which is crucial for the way the game is played now, looks smart and instinctive. Light (230 pounds) and has issues shedding blocks.
The three rookie WRs are a lot like the three RBs last year, on any given day any one of them can look better than the other two. Valdes-Scantling has flashed the most potential but needs to work on his hands. St. Brown didn't do much, at least from what I saw, early in camp but has come on and made more catches in practice recently. Moore looked most impressive in the offseason because he seemed to get in and out of his cuts fast, but has had drop issues, as we saw in the game.
JK Scott: Has been pretty impressive in camp, consistently gets a lot of hang time, more often than not with pretty good distance too.
Don't have much of a feel for Looney and Donnerson. Neither has jumped out in team or in the couple times when they've done one-on-ones.