0.4 Fubgun Poisonburst Pathfinder

Make sure to fill out your resist, you want 75% fire/cold/lightning resist. Chaos resist is good, but not mandatory to have 75%, I usually aim for 30-50%.

Do note you will most likely need 1 high attribute roll on your gear (either int or dex) to fill out your attribute requirements - or you sacrifice 2 passive points for Proficiency

Bow: You want the highest DPS weapon you can afford with critical strike chance - Obliterator Bow is the go to base because it has extremely high base damage, but any bow base works - Any elemental damage also works because we're using Plaguefinger
Voltaxic Rift Is an okay starter bow if it's cheap, the downside is the bow has 0 base crit so it'll quickly get replace by a good rare crit bow.

Quiver: Want high crit/crit damage with high flat damage, other good stats are increased damage with bows, atk speed and +2 level to bow skills.

Rings: You just want high flat damage rings, just like with the bow, the element doesn't matter because of Plaguefinger

Gloves: Plaguefinger is by far the best in slot option, makes gearing extremely easy as it allows you to stack elemental damage on rings/bow/quiver and allows you to use strong unique jewels.
These gloves are very strong but not mandatory, you can play this bow with pure phys on weapon/rings, it'll just be lower dps. If you don't have these gloves than the ele dmg on your gear does nothing, just stack flat physical damage and get an obliterator bow with high %phys.

Belt: Headhunter is always the best in slot for mapping, but never needed. Just use a regular rare belt with str/resist/life if you can't afford HH

Amulet: The only mandatory stat here is 30 spirit. Besides that crit/+level to proj is always good for damage. Global defense/increased energy shield are good for defense.

Helmet: You want the highest energy shield helmet you can afford, this is very important for defense because you take Subterfuge Mask

Body Armour: Hyrri's Ire Is easily the best in slot but not required, if you can't afford it just buy the highest evasion body armour you can afford, preferable with deflection rating.

Boots: Just want high movement speed and either life or %ES/Evasion, preferable with deflect rating.

Jewels: Get one jewel with %mana on kill, this will make your mana feel extremely good for while mapping. For unique jewels, Against the Darkness with any extra mod is fine (cold/fire/light/chaos)
Heart of the Well with 2 gain extra mods is also ideal.
For regular rare jewels, you just want crit/crit dmg/magnitude of poison
4 Mod Rare Radius jewels are also extremely strong but will be expensive

Anoint:
For damage: Leeching Toxins is what I recommend as you also get %life on kill
For defense: Patient Barrier Decent option for more ES