Homebrew Ghost Species Details

Ghosts are once-living adventurers back from the dead, which could have been in a variety of ways - a revivify spell gone wrong, a God deciding the adventurer still has work to do, or any way you choose. They are translucent, but rarely don't interact with things they touch. They no longer need to eat or drink in order to survive, and they can't do it at all.

Ghosts hover around, and if they came back is because someone revived them, they have to follow them around. Dying of old age is not usually a problem for ghosts - depending on how they came back, ghosts have different ways of leaving the world. If their reviver dies, the ghost will slowly fade away, fully disappearing from the world after 100 years. Ghosts gather in the North of the Sword Coast in the Forgotten Realms, and creatures who wish to find them usually go to the (literal) ghost town of Alendar, abandoned centuries ago but friendly to most creatures visting, unlike the other towns North of it. Passing through objects its physically straining for a ghost, so going underground is rare. 

Ghost Traits

Ghosts are specifically skilled in some aspects thanks to their unique constitution, and share some traits with their previous races

Ability score increase

Your Wisdom Score increases by 2, and your Intelligence Score increases by 1

Evillish

You are proficient in intimidation

Ghostly presence

All creatures can pass through it as difficult terrain

2 charges, expend both to negate an incoming attack after all rolls have been made, or just one to move through up to ten feet of solid

Stomachlessness

Unable to consume food

Passover

Choose whichever race you were before death, and your size is their size, and you get 2 traits from its racial traits list

Darkvision

Can see 60 feet without a light in the dark