Hull’s retained list, released yesterday, confirmed the exit of the duo along with Greg Luer, Josh Clackstone and Greg Olley.
McGregor has already agreed a switch to Rangers, while Meyler will consider his options once the upcoming trio of friendlies for the Republic of Ireland against Celtic, the United States of America and France are out of the way.
Meyler made 191 appearances and netted 19 goals during five and a half years with the Tigers.
The duo’s departure means none of the 18 players on duty against Arsenal at Wembley four years ago is still at the KCOM Stadium.
Steve Bruce, in charge as the Gunners came from behind to triumph 3-2 after extra-time, also left in the summer of 2016, just a few weeks after Hull had clinched promotion by beating Sheffield Wednesday in the Championship play-off final.
A further indication of how quickly things have changed in the East Riding comes via there being a distinct chance everyone involved in that win over the Owls will have left the club by the start of next season.
Certainly Michael Dawson and Abel Hernandez are expected to depart despite being offered new contracts by the Tigers in recent days.
That would leave just Moses Odubajo, another who is out of contract this summer.
The full-back has been offered a new deal, but his plans are unclear with former manager Bruce understood to be keen on being reunited with the Londoner at Aston Villa.
If Odubajo follows Dawson, wanted by Nottingham Forest, and Hernandez out of the KCOM then all 18 players in the squad that beat Wednesday thanks to Mo Diame’s strike will have left.
The Tigers have offered contracts to Max Clark and Seb Larsson. Under Football League rules, the duo have a month to respond.
Elsewhere, Adam Hammill leads the exodus at Barnsley following relegation to League One.
The Liverpudlian, a key figure in the club’s promotion two years ago, is joined by Andy Yiadom, Matt Mills and Nick Townsend in heading out through the exit door.
The Reds, without a coach following Jose Morais’s abrupt departure on the final day of the season, have offered a new deal to Jack Walton, who started the final three games of the Championship season.