There aren't many "EDGE" players whom I think would be a schematic fit that are Free Agents. Still kinda surprised that the Pats haven't at least kicked the tires on Matt Ionnidis as a replacement for Ekuale, but that could be more about what he's looking for in a contract.
There are supposedly some Edge players available for trade:
Atlanta - DeAngelo Malone - 3rd round pick in 2022. Has been relegated to Special Teams now that Dean Pees is no longer the DC there. 6'3 2/8 inches, 243 lbs. Out of Western Kentucky. Malone is just 24, so plenty of time to mold him..
Philly - Derek Barnett - He's at the back end of Philly's rotation. He's in the final year of a Contract so shouldn't cost much. He's HEALTHY this year, which is good because he is pretty decent when healthy. He seems to be the most well-rounded option of what's available. Barnett is 27 and will be 28 in June.
Seattle - Darrell Taylor - Another guy who is the odd man out in an edge rotation. Been very good in rotation for his 1st two years. Has the size the Pats seem to look for and still relatively young. He's improved his tackling since his rookie year. His one downside looks to be on setting the edge.
Others considered/Rejected :
Houston - Jerry Hughes
Green Bay - Preston Smith
NY Jets - Carl Lawson (don't see the Jets trading him to the Pats)
Washington - Montez Sweat / Chase Young - Too Expensive. Would require a 1st round pick at the minimum.