A kiosk in Akihabara sells a vast array of milk drinks.
When I first came to Japan, I was surprised at the array of milk beverages. They don't just have low-fat and whole milk, but they have a wide range of fat concentrations from 0% to 4.4% fat. Skim milk with no fat is actually a little tricky to find, though low fat milk below 1% is common. There are also many flavored milks. I recall a product called "The Coffee Milk" (in English) that caught my eye when I first arrived. Fruit-flavored milk drinks and milk flavored with more native flavors like green tea and kinako are also available depending on the season. Note that all milk that I have encountered in Japan is cow's milk. These variations do not include sheep's milk, goat's milk, etc.
Japanese people tend to drink milk for health purposes rather than enjoyment in my experience. I've never had anyone say, "I love milk." As a kid, I grew up adoring milk and my family went through copious amounts of it so seeing milk as a healthy beverage rather than for pleasure was not something I was accustomed to. One of my former coworkers at a Japanese office used to drink a liter of it every day for his health. His colleagues (not me though) nicknamed him "gyunyu-san" ("Mr. Milk") for his habit. He didn't like that, unsurprisingly.