When running hexcrawls, I tend to pack my hexes pretty dense. This means there's usually multiple points of interest to choose between in an individual hex. For this reason, I generally assume the party is able to find some kind of vantage point to get basic info on all points of interest that aren't specifically hidden. However, I find my mind frequently returning to the easiest answers. In the plains? You find a lone hillock. In the forest? Big-ass tree. You get the idea. This is fine, that's going to be most of the vantage points one would realistically encounter, but I still want to shake it up and provide vantage points that create their own set of complications from time to time.
Below are 36 unusual vantage points and possible complications to scaling them, 6 for each basic terrain type. I've tried to make it so each requires some kind of risk or expenditure for the party to weigh against the time cost of looking for another spot (I'd probably go with 1 watch). You can roll (or pick) from the terrain in question, or roll a d66 on the table at large. Though the results fit best with their associated terrain, few would be more than a little out of place in others.