Crooked Men have a solid ranged "attack" (it's a spell) that does lots of blasts at 10" range. They also synergize amazingly with Belles, as they can drop down Shafted markers (land mines) and have the Belles drag models into them. The Drowned are a new option, cheap super tanky spirits which have a close ranged spell and attack, their goal seeming to be to spam DF duels across tightly packed opponents. Crooked Men and Drowned seem similar in roles, I prefer Crookeds for Shafted Markers and better damage, but Drowned are faster and harder to kill. A toss up.
Autopsies have guns, which have a baked in + on the the damage flip, which is nice, but they are slow and easy to kill. Generally considered sub par.
Convicts are baller, no matter faction you're in. With Seamus, Lure them in and have the two of them light some poor sucker up. Onyro have a decent ranged spell as well, and are just a fantastic piece to include in your army for their durability and debuffs.
Dead Doxies are dead Performers, but with a damage focus. They are fast (Wk 5, boosted to 7 when near Seamus) and have a spell which they cast at Ca 7 (resist WP) that pushes them their walk towards the enemy, and then can immediatly cast Seduction (-- on defense flips) and shoot or stab them. And it's a zero action, so with a 6" range on their gun they can easily attack 3 times and cast a spell with a threat range of 13". They don't do a ton of damage, nor are they accurate, so I see using them to attack models other Belles have debuffed. And my favorite ability that they have is a (1) action that can only be used as a Slow to Die action, where they push to a friendly Belle and steal some of their Wounds to stay alive.
So Ressers doesn't have a lot of ranged pieces, and most of them are really ranged with a twist (either shorts ranged and fast or spell based), but I've had success with a lot of shooting in my Seamus crews. I've played as Colette against Seamus (though without Cory), and those Belles are extremely disruptive to your play style. Seamus can very easily drag in one model at a time, and ruin your day when it comes to trying to complete objectives.
All in all, to finish a really long winded post, Seamus is the man. A very versatile piece, he has a ton of control abilities that he and his crew brings to the table that make him a blast to play. And with his Avatar form out now, he can decide to just hulk out and smash in their skulls (while scaring them out of their wits). Best Malifaux purchase that I've ever made.