There are several types of stairlifts available, including straight stairlifts, curved stairlifts, outdoor stairlifts, and standing stairlifts. Straight stairlifts are designed for staircases with no curves or turns, while curved stairlifts are custom-built to fit staircases with curves and turns. Outdoor stairlifts are designed to withstand outdoor weather conditions and can be installed on outdoor staircases. Standing stairlifts are designed for users who have trouble bending their knees or sitting down.