There are 3 Sage Areas in the Naruto World. The Mount Myoboku, Ryuchi Cave, and the Shikkotsu Forest.
Here are all 9 different characters that have visited these three Sage Areas.
10. Tsunade Senju
Tsunade Senju is affiliated to the Shikkotsu Forest. She signed a summoning contract with Katsuyu, the Princess Slug of Shikkotsu Forest. This allowed her to go to the Shikkotsu Forest, or summon Katsuyu anytime.
9. Hashirama Senju
Hashirama Senju was a user of the Sage Mode. While we don’t know which Sage Place he was affiliated to, he certainly doesn’t belong to Mount Myoboku, and Ryūchi Cave. Which leaves only the Shikkotsu Forest. I’m certain he was affiliated to Shikkotsu Forest as well.