I dunno what tribal style is really, but . . .
The first one registers as a sort of skull-with-tusks shape after a while. It also makes me think of the buff icons that flash over your head in World of Warcraft and such.
The second one, with that pentagram-heart shape; it looks almost like the shapes to either sides are flanking gryphons or something along those lines, giving the whole thing a bit of a heraldic look. Probably the best color on this one.
The third one looked a little like “something evil is looking at you from the abyss”, but I couldn’t get enough brightness into it to actually see what was going on there.
The fourth one looks a little like a hybrid of the Tribal Wings chest logo in City of Heroes and the old Quake logo. The shape is a little drowned out by the hammertasticness of the metal, though.