Team counts of most MLB home runs by individuals by year.

1916-2018: 15 of the 30 teams had a player hit the most home runs in a season more than once. 20 of the 30 had a player lead ever: 67%.

Query1

franchID	Num	LastOfname	HRmax	HRmin	YearFirst	YearLast	theLast1	theLast2	theFirst1	theFirst2
NYY	17	New York Yankees	61	12	1916	2007	Alex	Rodriguez	Wally	Pipp
SFG	11	San Francisco Giants	73	12	1916	2001	Barry	Bonds	Dave	Robertson
PHI	11	Philadelphia Phillies	58	12	1917	2008	Ryan	Howard	Gavvy	Cravath
CHC	9	Chicago Cubs	56	12	1916	2000	Sammy	Sosa	Cy	Williams
OAK	9	Oakland Athletics	58	11	1918	2018	Khris	Davis	Tillie	Walker
BOS	8	Boston Red Sox	46	11	1918	1984	Tony	Armas	Babe	Ruth
DET	8	Detroit Tigers	58	34	1935	2012	Miguel	Cabrera	Hank	Greenberg
PIT	8	Pittsburgh Pirates	54	37	1947	1973	Willie	Stargell	Ralph	Kiner
STL	6	St. Louis Cardinals	70	39	1922	2009	Albert	Pujols	Rogers	Hornsby
ATL	5	Atlanta Braves	51	28	1945	2005	Andruw	Jones	Tommy	Holmes
BAL	5	Baltimore Orioles	53	40	1966	2016	Mark	Trumbo	Frank	Robinson
TEX	5	Texas Rangers	57	43	1968	2003	Alex	Rodriguez	Frank	Howard
CIN	4	Cincinnati Reds	52	40	1954	1977	George	Foster	Ted	Kluszewski
MIN	4	Minnesota Twins	49	44	1963	1969	Harmon	Killebrew	Harmon	Killebrew
TOR	3	Toronto Blue Jays	54	40	1986	2011	Jose	Bautista	Jesse	Barfield
ANA	1	California Angels	39	39	1982	1982	Reggie	Jackson	Reggie	Jackson
MIL	1	Milwaukee Brewers	39	39	1982	1982	Gorman	Thomas	Gorman	Thomas
CLE	1	Cleveland Indians	50	50	1995	1995	Albert	Belle	Albert	Belle
SEA	1	Seattle Mariners	56	56	1997	1997	Ken	Griffey	Ken	Griffey
LAD	1	Los Angeles Dodgers	48	48	2004	2004	Adrian	Beltre	Adrian	Beltre
FLA	1	Miami Marlins	59	59	2017	2017	Giancarlo	Stanton	Giancarlo	Stanton

Most MLB home runs by individuals by year. Wednesday, September 11, 2019

Mark McGwire actually led five times. In 1997 he played for Oakland and St. Louis and hit 58 home runs but did not lead either league. Ken Griffey got credit in 1997 with 56 home runs, his only time leading MLB...

The New York Mets have never had a player lead MLB in home runs in a season but rookie Pete Alonso currently leads in 2019 with 47.
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So the Seattle Mariners should not be listed with a players hitting the most home runs in a season.

In addition to the Mariners teams that did not have a player hit the most home runs in a season 1916-2018:
Chicago White Sox, Mets, Astros, Royals, Padres, Washington Nationals (Montreal Expos), Diamondbacks, Rockies, Rays. The White Sox were active 1916-2018. All the other teams are modern expansion teams. The Mets and Astros are the oldest among these, having started in 1962.

The Yankees have had a player (actually 7 players) hit the most home runs the most times primarily because of Babe Ruth doing it 9 of the 17 times, including 1931 when Ruth and Lou Gehrig tied for the AL and MLB lead. But the Babe is neither the first nor the most recent Yankee. Check the matrix below.

qryHomeRunKingYearMLBplayers

yearID	MaxOfHR	lgID	franchID	teamID	playerID	nameFirst	nameLast	bats	name
1916	12	AL	NYY	NYA	pippwa01	Wally	Pipp	L	New York Yankees
1920	54	AL	NYY	NYA	ruthba01	Babe	Ruth	L	New York Yankees
1921	59	AL	NYY	NYA	ruthba01	Babe	Ruth	L	New York Yankees
1923	41	AL	NYY	NYA	ruthba01	Babe	Ruth	L	New York Yankees
1924	46	AL	NYY	NYA	ruthba01	Babe	Ruth	L	New York Yankees
1926	47	AL	NYY	NYA	ruthba01	Babe	Ruth	L	New York Yankees
1927	60	AL	NYY	NYA	ruthba01	Babe	Ruth	L	New York Yankees
1928	54	AL	NYY	NYA	ruthba01	Babe	Ruth	L	New York Yankees
1929	46	AL	NYY	NYA	ruthba01	Babe	Ruth	L	New York Yankees
1931	46	AL	NYY	NYA	gehrilo01	Lou	Gehrig	L	New York Yankees
1931	46	AL	NYY	NYA	ruthba01	Babe	Ruth	L	New York Yankees
1934	49	AL	NYY	NYA	gehrilo01	Lou	Gehrig	L	New York Yankees
1936	49	AL	NYY	NYA	gehrilo01	Lou	Gehrig	L	New York Yankees
1937	46	AL	NYY	NYA	dimagjo01	Joe	DiMaggio	R	New York Yankees
1956	52	AL	NYY	NYA	mantlmi01	Mickey	Mantle	B	New York Yankees
1961	61	AL	NYY	NYA	marisro01	Roger	Maris	L	New York Yankees
2007	54	AL	NYY	NYA	rodrial01	Alex	Rodriguez	R	New York Yankees