I recently rediscovered four forgotten operators in Darwinbots. They are clear, drop, swap, and over. Why do I call these the forgotten operators? Because there was no reference to them anywhere on the wiki. Anywhere. Absolutely no mention or documentation.
The wiki had entries for clearbool, dropbool, etc. for the Boolean stack, but it did not list their integer stack equivalents. These forgotten operators seem fully functional, and I have no clue why they were not listed anywhere. They seem very useful.
Anyways, I created a category of operators on the wiki called "Stack Operators" which includes clear, clearbool, drop, dropbool, etc (6 pairs in total).