What kinds of visual aids have you used in your games? I'm talking beyond Maps and Minis.
Which aids have had the most impact on players?
Which aids have caused disruption or distraction?
What's the effect when the aid is reused in the same (or later) campaign?
One I've mentioned before I use with various groups.
In my campaigns I have it that coins of the land analog to various US coins. A copper piece is about the size of a penny. A Silver piece about the size of a nickel.
So I have a mason jar full of approximately 1000 pennies to show players what sort of volume that many coins will take up. I also have an aspirin bottle filled with 100 nickels as its a good example of how many might fit in a coin purse.
Lots of photos and pics off the Internet for monsters and NPCs.
I once created a fake newspaper to present to players every few sessions (really it was just a front page I would reformat between 2 or 3 styles); featuring a new front-cover story/picture and usually one or two little mini-columns (often added simply for humor like stupid ads or caustic op eds, but not exclusively).
I would seed little pieces of information related to what was happening in the city, amusing anecdotes related to the PC's exploits, etc. which was more useful than a newspaper/gazetteer/etc. in an average campaign because superheroes were a prime facet of that particular game; as a result, big crimes or the activities of gangs/other supers would be reported on fairly frequently and the connected events and people would often be relevant to the party and the larger campaign ecosystem.
I rarely use any visual aids.
The most successful ones I've done is when I make a map/scroll that is doctored up to be partially mangled/burnt/torn/smudged/dirty/etc. and let the players make of it what they will. I do that maybe once every 2 or 3 years, when I'm sure that the thing is in a place that the characters are almost sure to find it or an NPC will simply hand it to them.
I am not sure if this counts as a "map", but I use 3D printed terrain a lot and it is well liked by my players.
The previous DM for the group I picked up when I moved was in the process of making a cloth map prop for his campaign when he passed away. The group gave it to me. Still have it.
I'll make my caveman doodles of various things and show them to players.
Example, for Deep Carbon Observatory, I made up some index cards that had colored drawings of the weirdo potions that one dude had on his belt because it was very important that they be absolutely clear which potion they were using.