Legs Up The Wall aka Viparita Karani is an easily accessible and widely beneficial yoga posture. This Restorative posture is a mild inversion as well and has many of the benefits you would receive from other inversions. Unlike most inversions you have the added benefit of being able to rest in this posture and hold it for long periods of time. Some even use this posture for a Savasana.
If you are unable to use a wall or don’t have access to a wall you can mimic this pose by using a block under your sit bones and lift your legs straight up to the sky.