There is 7 traits in the game but I've never reached to get all 7 on one monster. I'm stuck at 5 traits atm:
View attachment 4368970
Well, you can't really get more is the sad and short truth without rewriting the CombineTrait code. You are rolling basically a 1/20 shot to get 6 traits. Also, with the addition of some new stuff, I can imagine we will be getting even more traits down the line.
Here is the relevant code section, btw.
C:
int num = Ut.GetRandomIndexFromChanceList(new float[]
{
40f,
30f,
15f,
10f,
5f
}) + 1;
Essentially those float values get passed to another method that randomizes a number between 0 and the combined total (100), and then counts each 'success' where the number in that array above is greater than the number rolled. So the max you can get (if it chose between 0 and 5 inclusive), is 5 + 1, or 6. Now you could rewrite it so everything is guaranteed, but I think that takes the very little challenge in breeding super monsters away.
Edit: The simple solution is just to make int num = list.count, btw. Or just delete the section entirely and replace the one instance of num with list.count in the while loop.