these icons change accordingly to what the command does. i think there are 3 types of graphics: one for the quicktexts, one for the plugins' commands and one for the rest.
the commands starting with and x (like /xunignore) are commands from a plugin that u installed.
and its weird cause ur icons look different to mine, maybe u have an older version?
Edited: u installed stuffplug ng, even in the picture u posted u can see in the tooltip that /xunignore is from that plugin...