As a followup to our email conversation after TPAC, here is the sub-list of items that were identified for searching/filtering:

• Any accessible information (any of the a11y metadata fields have content)
• Conformance information (dcterm:conformsTo)
• Certification information (a11y:certifiedBy)
• Accessible Math (MathML) (accessibilityFeature = MathML)
• Supports Visual Adjustments (accessiblityFeature = displayTransformability)
• Supports nonvisual reading (accessModeSufficient = textual )

with an open question for: 'do not search/filter on hazards, but it may be critical to always be able to show the presence of claimed hazards in any search/filter return'