Is it possible that the files and templates could (should?) be part of separate role that you perhaps pull in as dependency?

The other pattern I saw out there was that the file/template wasn't part of the roles, but was instead provided by playbook that is using the roles. So file was in repository with playbook and template/file path was passed to role as parameter.

As an alternative to what @mea_rah proposed, you can also push your files in a git repository that you can clone/pull on your remote hosts (or locally, then copied / templated out, if needed) from a separate task, which can be in or out (via include_tasks or import_tasks modules) of your roles. Or if all target hosts have access to a shared storage, you can directly copy files from there, depending on your needs.

I still think having your files and deploy task on a separate role used as a dependency for your other roles is the way to go, though I'd need more context to give you a more appropriate answer.

Symlinks are the simplest solution (just checked, it works)

$ tree test-role*
test-role1
├── tasks
│  └── main.yml
└── templates
    └── template1.j2
test-role2
├── tasks
│ └── main.yml
└── templates
    └── template1.j2 -> ../../test-role1/templates/template1.j2

$  cat test-role1/tasks/main.yml 
- name: copy template
  tags: test-role1
  become: yes
  template:
    src: template1.j2
    dest: /root/template1

$ cat test-role2/tasks/main.yml 
- name: copy template
  tags: test-role2
  become: yes
  template:
    src: template1.j2
    dest: /root/template1

$ ansible-playbook playbook.yml --diff --check --tags test-role2
...
TASK [test-role2 : copy template] *****************
--- before
+++ after: /home/deploy/.ansible/tmp/ansible-local-143602q8imzfz/tmp8g6dn_h1/template1.j2
@@ -0,0 +1 @@
+this is a template