There was a guy (Mechatails) who had a claw-centered build, he called it the "Clawlander". Unfortunately his build data was on the original Runic forums which is gone now.

I have been using pistols with Rapid Fire and enjoying them but I saw someone do an acid rain build that looked comprehensively better.

I've done some Outlanders with a Chaos Burst build, and others with a Sandstorm build. I usually change up the type of weapon I'm using for each build, as well. So, if the previous Outlander was using dual wield pistols, the next one might use a Bow or a Shotgunne instead. I'll even deliberately use the wrong type of weapon sometimes, such as giving my Outlander a melee weapon, or giving my melee character a ranged weapon.

引用自 ❤Simone Pianetti❤：

In the past I played outlander HCE with the standard shotgunne + rapid fire + all the passive, this was boring as hell (I dont like outlander overall)
Is there a fun outlander build? I'm playing on normal so everything can work

Most games that build on passives tend to be boring since there's no need to provide extra manual input.
Investing more Actives that reach more of the screen and can be interacted with will raise the fun value in games like these and other Rpg genres in general.
For Torchlight_2 Outlander - there's plenty of enjoyable skills to invest since range is not an issue for Outlander.

1st Tree:
Rune Vault is an acquired taste that many players don't like although it'll provide quick mobility.

Chaos Burst is much more enjoyable to use instead of Rapid Fire (for me) since the random nature of the projectiles and their ricochet offers good reach against crowds and won't burst a single target too quickly. Cursed Daggers is less fun however offers DeBuff.

Vortex Hex is great to trap enemies for crowd control.

Venomous Hail is the be-all; end-all ultimate for Outlander damage builds.

2nd Tree:
Any of the Glaive Skills offer an interesting alternative to Weapon-Projectile Skills.

Bramble Wall is a secret deep game strategy that can be paired with Item Skills to enact battle effects like Glacial Spike from Weapons when destroyed. Tends to fare best in the late game.

Burning Leap will be interrupted on targets however makes a decent escape skill if empty space is available.

3rd Tree:
The Pacts are the same tactic as Berserker's Battle Standard. If the Player enjoys manually managing the re-emplacement of the effect circle then the benefits help. Truly fun in maps that don't require far movement like Grom's Arena however this is rare.

Shadow Shot is no Chaos Burst or Rapid Fire however it's a decent alternative.

Bane Breath is the least liked among Players and it's super wonky. If the Player doesn't mind Melee Range then the benefits of spawning Shadowlings is decent.

Repulsion Hex if seeking to keep Melee enemies away from Ranged builds.

Shadow Mantle is the lesser option compared to Berserker's Ice Shield. Still decent. Acts more like a temporary passive.

Shadowling Brute is the lesser option compared to Engineer's Sledge Bot on time available yet is decent to help Shadowling builds.