I have used this one on my forum
https://vborg.vbsupport.ru/showthrea...t=prevent+spam
It prevents users from using specific words until they have "x" amount of posts. So i use the field like www, and http to prevent xrated images and undesirable links. If they do put one of these words into their posts without having the designated amount of posts the thread or post is placed into moderation for approval or denial.
The problem I am having right now is they must of found a way to get around this because they are putting their ad links into their signature