Gray would be a good pickup but will be less costly in terms of giving up value to sign a veteran free agent SP than trading away players/prospects.
An interesting guy is Kyle Gibson. Did not get a QO and has averaged 30 starts per season over last three years. Age 32 but actually ticked up in velocity in 2019, with good K rate and lots of grounders. A bit homer prone but, if no TORP addition as seems the case, could be a good pickup to replace Hamels or if Q is trade bait. Jon Heyman says 10 teams are interested in him.