Here are a couple of links of sign dictionaries I use and have students use to  find STEAM signs. 

This is my youtube channel with a bunch of science-related videos. They aren't perfect,  but it is a place to start. 

From CAST, ideas for incorporating UDL in higher education.

AEM provides resources and technical assistance for educators, parents, students, publishers, conversion houses, accessible media producers, and others interested in learning more about AEM and implementing AEM and the National Instructional Materials Accessibility Standard (NIMAS).

Here are guidelines on generating accessible media: http://aem.cast.org/creating/accessibility-perceivable.html#alttext