You could also use IFTTT and trigger it using the Dominos service, triggered by opening a URL with Stream Deck.
So the IFTTT trigger would use https://ifttt.com/services/maker_webhooks and the action would be the Dominos easy order action.
Depending on how much of your own design you want your icons to be.
So far i seem to get the best consistency in my icons using the Key creator. https://www.elgato.com/en/gaming/keycreator
Combined with iconfinder. https://www.iconfinder.com/
(Download the png /svg and upload them as an image in the creator)
Even most of the paid ones are usable in their free mini version.
There is another way - Photopea gives a rough photoshop version online which is surprisingly accurate and similar.
A link for my Key Editor: https://www.photopea.com/#iuS3c_Mo7