Tattoos from the following DLCs will be added in the next patch:
Criminal Enterprises
The Contract
Arena War
Los Santos Drug Wars
That means all the missing tattoos should be available.
I better post here as well. Maybe some of you remember me. Thang Rashilow and Jospeh Couch. I'm still in touch with quite a lot of people from vG, so if you lost contact with someone I could try to help out.