Kekkei Genkais are not only one of the most important plot devices in the series, but they are also very powerful techniques that are bestowed on either a person or clan, as we all know. Thanks to Kishimoto's creative genius, we have seen multiple different types of Kekkei Genkai, ranging from special eye abilities to body manipulation powers. Today however, I want to specifically focus on Nature Transformation Kekkei Genkai/Tota, which have created some of the powerful jutsu in the series.
To start, my preferred Kekkei Genkai Nature Style would be Lava Release, which I must say is all due to my love for the Four-Tails and his Jinchuriki Roshi. It is very versatile, due to its unique property to manifest as different forms depending on the user. For example, Mei can spew hot lava from her mouth, Dodai can spew a rubbery-like substance from his mouth, and Kurotsuchi and Boro are able to use volcanic ash. I would personally choose Roshi's style of Lava Release, in which he is able to spew hot magma from his mouth, and literally coat himself in lava. He's really only able to do this because he's the Jinchuriki of Son Goku, who actually possesses the Kekkei Genkai, but that would just be an added plus.
In the comments, if you guys commented on which one you would pick and maybe explain why, I think it could lead to some really interesting discussions and overall be fun.