Here are a list of players he has been outscored by in the playoffs, I made this when he had 23 in 55, now he has 25 in 65:
Obvious ones:
Mark Messier (35 in 54, 5 stretches of equal/better than 23 in 55)
Wayne Gretzky (42 in 52, 11 stretches)
Jari Kurri (41 in 55, 9 stretches)
Mario Lemieux (40 in 49, 10 stretches)
Kevin Stevens (30 in 45)
Paul Coffey (27 in 52)
Jagr (34 in 50 6 stretches)
Brett Hull (40 in 51, 9 stretches)
Bobby Hull (34 in 50, 6 stretches)
Mike Bossy (51 in 56, 10 stretches)
Phil Esposito (34 in 46, 4 stretches)
Joe Sakic (33 in 51, 6 stretches)
Maurice Richard (31 in 34, 7 stretches)
Jean Beliveau (35 in 51, 5 stretches)
Esa Tikkanen (25 in 40)
Bryan Trottier (23 in 39)
Gordie Howe (29 in 55)
Evgeni Malkin (24 in 46)
Sidney Crosby (24 in 43)
Connor McDavid (26 in 53, 3 stretches)
Leon Draisaitl (30 in 49, 4 stretches)
Nathan MacKinnon (30 in 45, 5 stretches)
Guy Lafleur (32 in 48, 4 stretches)
Bernie Geoffrion (36 in 53, 6 stretches)
Cam Neely (39 in 54, 4 stretches)
Johnny Bucyk (27 in 46)
Pavel Bure (27 in 47, 3 stretches)
Alex Ovechkin (30 in 51, 4 stretches)
76
Patrick Marleau (25 in 46)
Brad Marchand (28 in 54)
Mats Sundin (equaled)
Rick MacLeish (24 in 34)
Bill Barber (30 in 51)
Joe Nieuwendyk (27 in 52)
Yvan Cournoyer (32 in 49)
Brian Bellows (23 in 47)
Joe Mullen (30 in 54)
Jacques Lemaire (23 in 45)
Brayden Point (28 in 46)
Denis Savard (29 in 48)
Peter Bondra (23 in 45)
Dale Hawerchuk (23 in 52)
Roenick (26 in 44)
Lanny McDonald (23 in 49)
Glenn Anderson (32 in 49)
Joe Pavelski (25 in 48)
Theo Fleury (24 in 37)
Rod Brind'Amour (23 in 51)
Rick Middleton (25 in 52)
Jeff Carter (24 in 54)
Rick Vaive (26 in 48)
Rick Tocchet (25 in 41)
Martin St. Louis (25 in 44)
Jake Guentzel (23 in 37)
Chris Kreider (24 in 43)
Zach Hyman (30 in 53)
Claude Lemieux (26 in 52)
Trevor Linden (equaled)
Kirk Muller (23 in 43)
Dino Ciccarelli (25 in 48)
Peter Forsberg (23 in 49)
Brian Propp (30 in 51)
Steve Yzerman (equaled)
Luc Robitaille (29 in 52)
Henrik Zetterberg (25 in 45)
Daniel Briere (27 in 46)
Stephane Richer (29 in 51)
Brian Leetch (equaled)
Steve Shutt (24 in 43)
Reggie Leach (31 in 43)
Tim Kerr (36 in 54)
Michel Goulet (24 in 51)
Jarome Iginla (27 in 52)
Craig Simpson (31 in 51)
Steve Payne (31 in 47)
Rod Gilbert (equaled)
Ken Hodge (equaled)
Phil Kessel (23 in 46)
Gregg Sheppard (26 in 50)
Brian Gionta (equaled)
Ron Duguay (24 in 54)
Darryl Sittler (equaled)
Bobby Schmautz (23 in 54)
Carter Verhaeghe (24 in 55)
Darryl Sutter (23 in 46)
Eric Lindros (23 in 48)
Robbie Smith (23 in 49)
Evander Kane (23 in 55)
Ted Lindsay (26 in 47)
Dickie Moore (26 in 51)
Mikko Rantanen (25 in 48)
Johan Franzen (25 in 39)
Bernie Nichols (25 in 51)
Peter McNab (24 in 36)
Adam Graves (26 in 53)
Here are some new ones after this years (25 in 65 for Matthews):
Mark Scheifele (24 in 50)
Doug Gilmour (26 in 60)
Brendan Shanahan (27 in 59)
Luc Robitaille (28 in 62)
Mike Modano (26 in 63)
Steve Larmer (25 in 59)
Nikita Kucherov (28 in 62)
Patrick Kane (28 in 65)
Daniel Alfredsson (26 in 60)
Brian Bellows (25 in 65)
Steven Stamkos (28 in 62)
Tarasenko (25 in 55)
Logan Couture (30 in 60)
Chris Drury (25 in 65)
Patrick Sharp (25 in 59)
Clark Gillies (25 in 65)
Scott Young (25 in 64)
Ken Linesman (25 in 61)
David Krejci (26 in 63)
Dave Andreychuk (25 in 65)
Vyacheslav Kozlov (25 in 65)
Bobby Clarke (26 in 65)
John LeClaire (25 in 62)
Mark Stone (25 in 65)
Vincent Damphousse (25 in 64)
Bob Bourne (25 in 63)
Pasta (25 in 57)
Russ Courtnall (26 in 64)
Shayne Corson (25 in 62)
Wendel Clark (25 in 59)
Simon Gagne (25 in 64)
Mats Naslund (28 in 64)
Pierre Turgeon (25 in 59)
Alex Delvecchio (26 in 57)
Gilbert Perreault (28 in 65)
Jim Pappin (30 in 62)
Peter Stastny (25 in 62)
Filip Forsberg (26 in 65)
William Nylander (26 in 64)
Danny Gare (25 in 64)
Bobby Orr (25 in 60)
Toe Blake (25 in 58)
Roughly 150 players