Well, tarantulas or other non-lethal invertebrates for me, and possibly snakes. As it suggest they are okay with that kind of things. And women who like bugs turn me on. But if they are those who handle dangerous animals, that's just dumb.
Also, I guess anything that suggest they are scientists?
Show some skills with a soil sampling device or something?
Stuff like swords or guns can make them cool, but that doesn't really translate as "attractive", to me, necessarily. Guns are scary. Women with guns are scary. I don't find scary women attractive. They scare me.