Hmm. Well, Joy as a cameo was a cameo gag of which we are doing several (a few more, non oots, but other webcomics, are coming soon).
Explosive runes has turned into an internet wide thing, I've seen that gag on several dozen comics now.
And, the dwarves being afraid of trees is an OLD gag. Much older than OOTS. It's a freaking Lord of the Rings joke.
So, I do see your point, but it is in many cases more a matter of OOTS and us taking from the same source, in parallels. (THere was also a recent strip in which one character stated, let's not steal a gag from the Giant. That was a rewrite, because I had already written a script using that gag, and then it was used in OOTS. I rewrote the strip to NOT use the same gag, but did a call out to it in the comic.)