When creating custom lists on a workspace, in some cases, these lists are only visible to admins. This solution shows how you can fix this by giving an audience access to view the list.
Navigate to the table sys_ux_applicability_m2m_list or go to https://<your instance name>.service-now.com/now/nav/ui/classic/params/target/sys_ux_applicability_m2m_list_list.do%3Fsysparm_clear_stack%3Dtrue
Create a new List Applicability record on the table, with your list and applicability. The applicability is your audience.
Sometimes lists have the same name as many others, for example: All is very common. If this is the case, click the search button when entering your list name, and filter by Sys ID.