Generally any morty in the top ~ 20 on this web page ought to certify. If you are fortunate adequate to find a hammer head morty at an early stage, stick with him. The mixed rating of each morty is his base HP plus the stat overall. Mortys are rated in order based on their combined rating.
I will do my best to upgrade the content here on time, no guarantees. In "A Rickle in Time" Rick tries to modify