hmm mostly in previous servers i was Client editor and packets changer , i can upgrade clients and give them a wanted icon and suchs , can even modify the WZ to have a GM version of them with super skills and even changing the weapon required to perform a specific skill
(in TerrorMS i made a version of assault with X2 distance range , unlimited amount of targets , X650 damage , 100% stun , and changed the weapon to 1 handed sword and i use it with my flaming katana so i own >.< )
i can also make scrpits but i don't have a lot of experience in that kind of scpirting , i can make a cilent that has infinite flash jump , swears , spam , infinite text , no dmg cap , no magic damage cap , i think i can also make no stat cap but i havn't tried before as 30k of all stats is pretty much fine either way.
the favorite packet i commonly use is scroll spam , when you are GM and want to superscroll item as you cannot modify its stats by yourself as only admin can do this , you use it , it makes 1 slot in the inventory spam scroll the selected item , and you just place the scroll in the slot (only available scrolls , food/pots will not be scrolling the item and will do nothing) so i can do around 2k scrolls on 1 item in less then 40 seconds and by that i dont need the admin to work for me =P.