Read Issac Asimov's Foundation series. Lot's of good ideas for exactly that.
For architecture, minature models of bridges, arches, with keystones etc archimedian screws windmills
For agriculture, models of beasts using the heavy plow, horse shoes
For metallurgy stone samples to what to mine for various ores in different stages of refinement with tableaux of how to build a forge.
For geometry "animated" (moving sticks and/or pieces of rope) proofs of pythagoras and other basic theorems on how to form bisectors etc
I'm having difficulty figuring out how to get realia for the more abstract abilities.
Bob
P.S. Oh and obviously a series of Tableaux depicting the life of Jesus and the creation, to give the poor unfortunates access to salvation if the cataclysm has been so devastating as to wipe out knowledge of the Divine.
Animate illustrations of a teacher teaching a student Latin and Artes Liberales out of the book they are illustrating.
Why do I have the mental image of a magus who builds this realia basically being the sort to make model trainsets? 