What mobs did you have in mind to hunt? From the highest dmg/sec on that list, it will be a low level one.
If you want to be as eco as possible, then i'd suggest trying to use a ranged weapon (assuming you have some skills in it). With more range between you and the mob, there would be less armor (if any) decay, and less fapping. The eco is generally better than a melee weapon too.
Good eco guns would be the opalo (very low decay and tt so no markup), or the cb5 blp equivalent (but (L)). For slightly higher dmg/sec try going for a korss 380, p4a, or a p5a for the extra dmg/sec. At the right markup, these are eco, especially if you slap an amp on them,
From the list you've posted there however, I personally would choose a rutik slo (L)