The adventure and stat gains for the Organ Grinder's pies are all currently 0 in fullness.txt. The relevant numbers are on the wiki. The adventure gains are 5-7 on liver and let pie, 7-9 on the elemental pies, and 8-10 on the badass pie.
The stat gains are listed as:
Liver and let pie: 5-10/5-10/5-10
stomach turnover: 5-10/16-20/16-20
Piping organ pie: 20-40/6-10/5-8
dead lights pie: 5-10/23-40/5-12
throbbing organ pie: 5-8/8-10/22-30
igloo pie: 15-19/16-20/6-10
shoo-fish pie: 19-30/20-26/11-30
badass pie: 10-20/10-20/10-20
The stat gains are listed as:
Liver and let pie: 5-10/5-10/5-10
stomach turnover: 5-10/16-20/16-20
Piping organ pie: 20-40/6-10/5-8
dead lights pie: 5-10/23-40/5-12
throbbing organ pie: 5-8/8-10/22-30
igloo pie: 15-19/16-20/6-10
shoo-fish pie: 19-30/20-26/11-30
badass pie: 10-20/10-20/10-20