Vertical dumbbell racks: These racks store dumbbells in a vertical orientation, often in a tiered design. They are space-efficient but may require more lifting to retrieve heavier weights.  

Horizontal dumbbell racks: These racks store dumbbells horizontally, making it easier to access heavier weights. They typically have two or three tiers and take up more floor space than vertical racks.

Single-tier dumbbell racks: These are simple racks with a single horizontal tier, suitable for smaller dumbbell sets or personal home gyms.