I find that most players don’t have much when it comes to non-hybrid rares. Most have the level 20 rares that make unique’s and that’s it. My primary account only has 6 level 20’s.
My 2nd account with 20 level 20 rares, I won 4 in a row for my 10 take downs. These were my choices and what I picked. If you have these, they do well. Elasmotherium was my MVP winning a 3-0 on one poor player and taking out two creatures in other battles. I had used Elasm previous weeks and always did very good.