Shade

Your roguish ability to utilise the shadows around you has taken on a whole new meaning. Perhaps you were born with half of your soul belonging in the Shadowfell, or perhaps an errant Shadow Demon was cursed to aid you. Whatever the case may be, you have found yourself allied with a creature made from pure darkness and have learned to work in tandem with this entity. 

Also, I did not originally create this class. I found it online somewhere but have since lost track of where. Pretty sure it was a freebie though.

One with Darkness

Starting at 3rd level, your Shadow companion manifests itself. You may use a bonus action to manifest a Shadow, whose statistics can be found on page 269 of the Monster Manual. The Shadow has its own initiative, which begins in the round immediately following the one in which it was manifested. It is a normal Shadow except for the following:

• The Shadow gains 1d8 health whenever you gain a Rogue level and you add your proficiency bonus to its AC and Attack damage, it gains proficiency in all saves, and it gains proficiency in 2 skills of your choice as well as keeping its proficiency in Stealth.
• When you gain an Ability Score Improvement, you may increase one of your Shadow's scores by 2, or two of its scores by 1, to a max of 20.
• The Shadow's Strength Drain ability no longer creates a new shadow upon killing a target. Instead, the Shadow regains HP equal to half the amount of damage the Shadow inflicted for the killing blow.

Finally, the Shadow lasts for an amount of hours equal to half your Rogue level or until its hit points drop to 0. When the Shadow reaches 0 hit points, it simply disappears until it is re-summoned. You may manifest your Shadow a number of times equal to your Intelligence modifier per short or long rest (minimum 1).

Throwing Shade

Starting at 9th level, you may use a bonus action to attach your Shadow to a weapon with the thrown property or a piece of ammunition. In addition, on a hit your Shadow appears next to the target and you may deal Sneak Attack damage. On a miss, your Shadow reappears by your side

Shadow Boxing

You and your Shadow learn to fight together. Starting at 13th level, whilst your Shadow is within 5ft of you, it has advantage on its attacks.

Slippery Shadow

Your natural rogue abilities transfer to your Shadow. At 17th level, Your Shadow gains the Uncanny Dodge and Evasion features.