The general rule is that the questions should be about the game Tibia. So any questions that are specifically asking about features of another fansite are considered off-topic and will likely be closed/removed. An example of such an off-topic question would be "Does TibiaWiki have a web API?". This doesn't have anything to do with the game as it's asking about a specific feature of another fansite.
It's however perfectly fine to mention other fansites (especially supported and promoted fansites), e.g.
Is it possible to check what bosses have spawned on my server? I've seen something similar on Tibiopedia.pl but I couldn't understand a word.
It's also perfectly fine and usually required to provide a source of the information you are providing. It adds credibility to your answer even if the source of the information is not in English (other users speaking that language can verify).
Finally, plain links are never an answer - "You can find it on Rookie.com.pl". I like how this image from Meta StackOverflow explains how links are not an answer:
Hopefully this helps!