I tried reading up on Muslim Coats of Arms, but I could find anything useful, which sort of left me a bit clueless about how to improve upon them.
It depends on what you mean by "Muslim" coats of arms. They followed many rules, depending on the culture. Turks and Altaic peoples used
tamghas as opposed to charges like Arab/Berber muslims.
Typically, the field was plain, although they did use teirced per fess (or per fess) as the next most-common division. They also used barry, bendy, and checky. These were basically the only ones used, an in almost exclusively (with barry, bendy, and checky being exceedingly rare).
Every color was used except purpure, and they also used 'self-colored' (or, bare metal, being silver/brown) as well. The rules regarding color were not as strict (as in the western rules for colors touching didn't always apply).
For
shi'ar(charges), it was quite common for many to be on one coat at the same time. For animals, they used lions passant, horses passant (but never without a depiction of a saddle), and eagles/falcons with wings displayed and inverted (think "pointing down"). They also used other physical symbols as indicators of rank (The Ayyubids were pretty formulaic with this). They used six- and eight-pointed roundels, fleur-de-lis (unconnected to the europeans, believe it or not), and crescents (which were meant to represent horseshoes). They also used pen boxes, shoes, tables, polo sticks, "trousers of nobility" (think paired drinking horns), axes, swords, napkins, banners, trumpets, paired pellet bows, lozenge shapes, and cups. The per fess division on
shi'ar meant that the shield usually was a solid color, or divided into three horizontal bands with lots of symbols (sometimes five or more). They were also occasional bits from al-qur'an on it ("God is Great"/"God is the Victor"/etc.).
The Turks/Mongols
tamgha system was essentially solid colors with centrally-placed symbols. The symbols look like strange interconnected gibberish, and the meaning of most is lost to history.