Sand, it's rough coarse and gets everywhere, and it makes for the perfect utility joker tree, the apple to Acid's orange.
Sandblast - Short-ranged blast of sand that damages and knocks back all enemies hit, giving you some breathing room. Combine with fire for burning sand that also blinds enemies.
Dust Devil - Utility option, creates a dust devil at a location that draws in nearby enemies, like a vortex. Perfect to combo with other AoE jokers. Combine with voodoo for a dark devil that also corrupts enemies.
Mudslide - The cowboy slides forward as the sand parts to either side of them, forming a cascade of mud that damages and knocks back enemies. Preserves momentum, and can be cancelled with a jump for epic movement. Slide into acid for a big acid splash at the end.
Sandcastle - Forms a castle tower of sand from beneath your feet, temporary high ground that enemies cannot climb. The best place to spray and pray into the cryptic crowds below. Combine with cactus for cactus needle arrowslits in the tower that fire at nearby enemies.
Sandstorm - Sand whips around in a massive storm centered on the cowboy, blinding enemies and making them attack blindly instead of aiming directly at players. Combine with electricity for a shocking storm that deals damage to those affected!