Tokyo Grutto Pass
If you would like to look around the museums in Tokyo (Actually it isn’t limited only in Tokyo though ) I strongly recommend you to try “Tokyo Grutto Pass”.
At present it is not on sales because of off-season but it will be on sale next from 1st April 2020 as described in above HP.
By using each ticket in Grutto Pass, you can enter the museum by free, or some hundreds yen discount.
It depends on each museum how much discount percent is though I can say if you have enough time and interest to look around some museums in Tokyo it is good value to use Grutto Pass.
*It is better to check if your favorite museums are included in Grutto Pass museums beforehand since some museums don’t participate this system.