I recently got back into penpaling because if Instagram!
I have a bullet journal and different type of journaling are very common in this community.
So an account I follow made a "find a penpal" post. You could write a comment with some information about yourself and people who were interested could comment on this.
Through this post I found 8 penpals in the beginning, but right now I only have stayed in touch with 4 of them. I found another 3 through a second post, so all in all I have 7 penpals right now, scattered all over the world!