Dice with pictures on one of the faces. Why? It might look pretty, but it makes the dice far less functional that it should be and, in some cases, creates unnecessary confusion. How so? Because some manufacturers put the picture on the six, and others put it on the one. Sure, after a few goes you remember what the picture means, but in the heat of a game it's annoying to constantly have to do the translation ("Little flag means six").
I mean - here are four dice with pictures or images in place of the one or the six. In three cases it's the one. In one it's the six. But which is which?
Spots or numbers, please. Anything else just isn't required.
These are sensible dice.
(Note: I have picture dice in my collection, mostly from shows or tournaments where they were given out as freebies. I never use them.)