While making maps for my D&D campaigns I found that I commonly wanted/needed a way to tell myself information that the players did not have access to that would not require me to make too many other clicks. So I eventually decided to make some map-markers that would represent all the information I could care to know about.
I should also mention that I am a patron of the program Maptools and that these tokens are intended to be placed on the hidden layer where only the DM can see them.
Furthermore, in Maptools (in case you weren't aware >.< ) if you double-click on an image that was dragged and dropped instead of drawn as a tiling texture, then you can enter in text in the 'GM Notes' section. If the image is not on the token layer, and there is some text either in the ordinary text field or in the DM notes field, then when you click on the image a text box will appear that shows the information you previously input. I use this function to detail traps, hazards, puzzles, or whatever else as need be.
Just in case you don't want all of them at once, I have taken the liberty of uploading zip files for each category as well as for all of them together:
Map Markers (All):
DC of Terrain = Movement Speed/ Level on Marker, if Level = 1 then movement is not inhibited but terrain warrants a balance check if run upon
DC of Trap = Level on Marker * 5
Relative DC of Monster Encounter: 1-3 = lower than the party's level, 4-6 = higher than the party's level
DC of door = Level on Marker * 5
DC of Puzzle = Level on Marker * 5
Quality of Shop = Level on Marker *5
The higher the level of the shop, the more goods AND/OR the better quality of goods sold there AND/OR the better prices found there.
Break DC = unspecified
Trap DC = unspecified
I may also add some in the future too.