@altopony
Subscribing to a gallery just notifies you when changes are made to it. If you want to save galleries for later and you’re on computer you could bookmark them and make a folder for your gallery bookmarks so you can easily find them again.
If you’re on mobile and have a notes app you could copy the links one by one and paste them into a note (label them for later) and then when you want to view one of the galleries you could open the note and easily find the gallery you want that way.
If those aren’t what you were looking for and you were wanting to mark them so they’re on your profile OR you didn’t like either of the above options, you can save the links to the galleries and put the links in your about me section using Derpibooru’s link feature which lets you easily add a link and label it so you know which is which.