[antihero]

Folks kinda works. I usually use "guys" when addressing people, but when being extra sensitive (eg, if I'm addressing a bunch of MTF trans girls), I'll be careful and use "folks".

To make a list, for things that I use in a "Hey ___, ..." context, with varying levels of casual:

    - Guys  
    - Folks
    - People 
    - You lot
    - Motherfuckers/jerks (other insulting term that's obviously not meant in earnest)
    - Mateys
    - Chaps (debatably gender biased)
    - Team (or other factual statement e.g. colleagues)
    - Everyone
    - Dudes (also debatably gender biased, but depends on how well people know you. I call everyone dude, I am probably immature)
    - Reprobates/scallywags/some other sort of old world sounding term.

[jnevill]

Yep. "Folks". I use it in all of my communications to my group (I am not the manager). I've tried others: "Guys" is clearly gender specific, "Ya'll" is pretty informal (although I use it on occasion), "Team" is barf-o-rama.

"Folks" works well. It's reasonably formal but not gross and, best yet, its inclusive.

[BrandoElFollito]

HN is a fantastic resource for non - native English speakers. "barf-o-rama" added to dictionary.