Y.A. Tittle has the most passing touchdowns for the Giants in a season, with 36 touchdowns in 1963.

who had the most passing touchdowns for the new york giants in a season, minimum of 25 passing touchdowns
1963Tittle2015Manning1962Tittle2010Manning2014Manning2011Manning1967Tarkenton2009Manning2016Manning2012Manning36353331302929272626
NAMESEASONTMGPTDCMPATTPCTYDSAVGYDS/GTD%INTINT%SCKSCKYRATE
Y.A. TittleY.A. Tittle1963NYGNYG133622136760.23,1458.6241.99.8143.8104.8
Eli ManningEli Manning2015NYGNYG163538761862.64,4327.2277.05.7142.32715793.6
Y.A. TittleY.A. Tittle1962NYGNYG143320037553.33,2248.6230.38.8205.389.5
Eli ManningEli Manning2010NYGNYG163133953962.94,0027.4250.15.8254.61611785.3
Eli ManningEli Manning2014NYGNYG163037960163.14,4107.3275.65.0142.32818792.1
Eli ManningEli Manning2011NYGNYG162935958961.04,9338.4308.34.9162.72819992.9
Fran TarkentonFran Tarkenton1967NYGNYG142920437754.13,0888.2220.67.7195.085.9
Eli ManningEli Manning2009NYGNYG162731750962.34,0217.9251.35.3142.83021693.1
Eli ManningEli Manning2016NYGNYG162637759863.04,0276.7251.74.3162.72114286.0
Eli ManningEli Manning2012NYGNYG162632153659.93,9487.4246.84.9152.81913687.2
StatMuse has season-level data for passing touchdowns going back to the 1921 season.