There are different minhagim as to how the shin is supposed to look on the tefillin shel rosh. Is there somewhere where I can view each of the most common minhagim? (Ashkenaz, Sepharad, Arizal, Chabad, Teiman, etc.) Maybe someone could provide pictures of each?
If what you want are simply pictures, I can present examples.
The first figure shows Beit Yosef, Ariza"l, and Sephardi shins for tefillin and the second, Chabad tefillin (and shin).
As far as I've seen, most Teimanim use the same shin as is found on Sephardi tefillin.