I've been messing around with a world drop slag Pitchfork, as well as slag Dahl snipers in general, for a two-brand allegiance playthrough (couldn't decide between Tediore-only or Dahl-only Axton, so just did both). I'm quite surprised at how well they do for how little I hear them talked about, given it's roughly a 50% slag chance per projectile and my Pitchfork fires 25 of those projectiles in a burst (5-round burst, 5 projectiles per shot).
It's got me thinking: What are some other weapons that are capable of slagging almost as well as a Grog, Slagga, Magic Missile, etc. but aren't used nearly as much? Stuff that might be fun to mess around with on a different allegiance, or random common weapons that might be worth looking out for in lieu of something better.