Here's a random top ten list of free agent wide receivers after this season. I'm sure someone else can dig more, but just a quick Google:
1) Tee Higgins, Cincinnati Bengals
2) Amari Cooper, Buffalo Bills
3) Chris Godwin, Tampa Bay Buccaneers
4) Stefon Diggs, Houston Texans
5) DeAndre Hopkins, Kansas City Chiefs
6) Diontae Johnson, Baltimore Ravens
7) Hollywood Brown, Kansas City Chiefs
8) Keenan Allen, Chicago Bears
9) Elijah Moore, Cleveland Browns
10) Mike Williams, Pittsburgh Steelers
https://www.profootballnetwork.com/nfl-free-agents-by-position/