Sombra by MagicPants

Tier 1:

Master Hacker: Quest: Hack enemy heroes 30 times without dying. Reward: Hacks duration on enemy heroes is increased by 1 second.

Improved Health Packs: Hacked Regeneration Globes heal for an extra 200 (+4%) health.

Improved Stealth: Activating Stealth will cause Sombra to be unrevealable for 2 seconds.

Tier 2:

Discus Throw: Increases the range of Translocator by 100%.

Long Barrel: Reduce the damage fall off of your basic attacks by 100%, dealing 2 (+4%) damage at max range, and increase your basic attack range by 2.

Rapid Fire: Increase your attack speed by 50%, but your basic attack range is reduced by 2.

Tier 3:

Ganked!: Your first round after breaking stealth will deal an extra 100 (+4%) additional damage. This round is not affected by range.

Ruthless: Killing an enemy hero that is Hacked will reduce its cooldown by 4 seconds.

Emergency Evasive: Taking damage while under 50% health will reset the cooldown of Stealth, this effect has a 20 second cooldown.

Tier 4:

EMP

Infiltrator

Tier 5:

Spy Games: Teleporting to a Translocator beacon will grant invisibility as long as Sombra remains stationary.

Regenerative Nanites: Activating Stealth will heal Sombra for 25% of her max health.

Shutdown: Hack can be used on enemy structures, shutting them down for 6 seconds.

Tier 6:

Tracking Rounds: Basic attacking a hacked enemy hero will cause your next clip of rounds to suffer no damage fall off.

Hacked Translocator: You can hack your own Translocator. Enemy heroes that come near it will cause it to explode, dealing 150 (4%) damage and silencing them for 1 second. You cannot relocate to a hacked Translocator.

Double Back: Relocating to a Translocator will drop a relocator at your feet before you teleport, allowing you to return to your original location.

Tier 7:

Electromagnetic Radiation: After activating EMP. Sombra will silence any enemy hero within melee range for a further 2 seconds.

Here and There: Infiltrator awards an extra 3 charges.

Need a Hand?: You can now Hack allied heroes, increasing their health regeneration by 2000% for its duration.

Hard Reset: Teleporting to a Translocator will reset the cooldowns of Hack and Stealth.

I came up with this idea as a hard counter to pesky heroes such as Genji, Tracer and Medivh, allowing her to shut them down effectively. However, due to her fragility, AA heroes such as Butcher, Raynor and Valla can deal with her easily, as can stealthed heroes that can hunt her down or ambush her at a locator beacon.

I was divided on whether she should be classified as a support or specialist, but I decided on support given that she can put out decent healing numbers if talented for it.