Gelbin Mekkatorque by Nortin

Tier 1
Repair Bot - Your trait becomes Repair Bot.
Emboldener 3000 - Your trait becomes Emboldener 3000.
Homing Chicken - Your trait becomes Homing Chicken.
Poultryizer - Your trait becomes Poultryizer.

Tier 2
Wrench-a-rang - Increase the range of Power Wrench significantly.
Arclight Spanner - Increase the cooldown reduction of Power Wrench to 4 seconds.
Homing Medpack - Rocket Launcher can be used on allied heroes, restoring a medium amount of health to them instead. Reduces the damage of Rocket Launcher by 50% when used on enemies.
Rocket Boots - Add Rocket Boots to the ability bar.

Tier 3
Energize - Shield Projector also grants 20% increased movement speed for its duration.
Static Field - Shield Projector also deals medium damage over time to nearby enemies for its duration.
Ballistic Rockets - Increase the range of Rocket Launcher by 50%, and its damage by 20%.
Infrared Goggles - Adds Infrared Goggles to the ability bar.

Tier 4
Gnomish Battlesuit - as above
Combat Mechanostrider - as above

Tier 5
Titansteel Wrench - Increase the damage of Power Wrench by 100% and its stun duration to 1 second, but increase its cooldown to 8 seconds.
Truesilver Wrench - Power Wrench no longer stuns, but also heals all allied heroes around Gelbin for a low amount.
Khorium Power Core - Increase the shield of Shield Projector to 30% of the target's maximum health and duration to 6 seconds, but increase its cooldown to 14 seconds.
Backup Batteries - Adds Backup Batteries to the ability bar.

Tier 6
Elemental Blasting Powder - Reduce the initial damage of Rocket Launcher by 30%, but it deals an extra 60% of its base damage over 4 seconds.
Blackrock Blasting Powder - Increase the radius of Rocket Launcher's explosion by 100%.
Saronite Lens - Shield Projector also grants 30 Spell Armor to its target for its duration.
World Shrinker - Adds World Shrinker to the ability bar.

Tier 7
Leystone Matrix - Increase the duration of Gnomish Battlesuit to 30 seconds. Gelbin also gains 30 Spell Armor for its duration.
Field Commander - Increase the passive movement speed bonus from Combat Mechanostrider to 30%. The active also resets the cooldown on Gelbin's trait.
Like Clockwork - Gelbin gains 5 Armor for every invention on cooldown.
Gnomish Jumper Cables - Adds Gnomish Jumper Cables to the ability bar.

-Power Wrench reduces the cooldown of Gelbin's trait and any actives he's taken from his talents.
-All active talents count as inventions, and benefit from Power Wrench and Like Clockwork.
-None of Gelbin's inventions cost mana.
-If the cooldown on Gelbin's trait is reduced enough to summon multiple of the same invention, the summons do stack. This means Gelbin can have two Repair Bots or two Emboldener 3000s at the same time.
-Talents that increase the damage of Rocket Launcher also increase the healing of Homing Medpack by the same amount.
-All inventions can be used in the Gnomish Battlesuit.
-Talents for Gelbin's abilities do not affect the corresponding abilities in the Gnomish Battlesuit.
-This is the appearance for the Gnomish Battlesuit:

This section contains my explanation and reasoning behind abilities and talents, so if that sounds boring, definitely skip it. I just like writing things maybe a little too much.

Abilities:
Gnomish Engineering (Trait) - Going to talk about traits in the talent section.
Power Wrench (Q) - Damage, ministun, and synergy with inventions. Basic ability, and the notion of a gnome smacking Diablo in the face with a wrench is great.
Shield Projector (W) - Shield ability because those are good on tanks and supports. Because he's a hybrid class, Gelbin can shield any friendlies he wants to.
Rocket Launcher (E) - Long range damage, and with a certain talent a core healing skill.
Gnomish Battlesuit (R1) - This was inspired by the Broken Shore from World of Warcraft: Legion, where Gelbin had a pretty cool mech suit. I was considering making this similar to Gelbin's second ultimate to avoid being too similar to Tychus, but I think it's fine. Might change it though.
Power Stomp (R1:Q) - Area of effect Power Wrench. Offers potentially huge cooldown reduction on inventions.
Shield Matrix (R1:W) - Area of effect Shield Projector. Good to beef your team up in a fight, may be too strong.
Rocket Barrage (R1:E) - Area of effect Rocket Launcher. Good damage, and with certain talents can be a potentially broken heal (may have to change)
Combat Mechanostrider (R2) - Based on the trusty mount of the gnomes. More movement speed at all times and mobility active, helps Gelbin maneuver around the battle.

Talents:

Tier 1
Repair Bot - The invention choice for dedicated supports. Constant heals that can be active half of the time, plus more often with Power Wrench.
Emboldener 3000 - A more versatile support-ish invention choice. Armor and damage are always good for the team.
Homing Chicken - A more offensive invention. Can disorient enemies while they try to destroy it, and damage them if they fail to.
Poultryizer - A control based invention. Not much to say, besides chicken.

Tier 2
Wrench-a-rang - Adds range to Power Wrench, makes Gelbin more versatile. Also, it's like a boomerang but a wrench. Could be a great animation.
Arclight Spanner - Based on an engineer item in World of Warcraft. Better invention cooldown reduction, can be good for builds that want the most value out of inventions.
Homing Medpack - An essential talent for dedicated support Gelbin. Gives him a good heal and more options for healing down the road, since damage talents for Rocket Launcher also affect Homing Medpack's healing.
Rocket Boots - Another invention. Burst of mobility, can be nice stacked with Combat Mechanostrider for lots of running around.

Tier 3
Energize - Adds some mobility to Gelbin's kit. Good for escapes, chasing, and generally anything mobility is good for. Don't like the talent name very much, so it may be changed.
Static Field - Damage aura on the shield. Good if Gelbin will be in the middle of things, or has an ally to buff that will be in the middle of things.
Ballistic Rockets - Offers both damage in general and better healing paired with Homing Medpack.
Infrared Goggles - An anti-stealth invention. With Arclight Spanner, can be very annoying for enemy stealth heroes.

Tier 4
Gnomish Battlesuit - As above.
Combat Mechanostrider - As above.

Tier 5
Titansteel Wrench - For a more aggressive Gelbin that wants the stun and damage, and is willing to sacrifice cooldown reduction on inventions.
Truesilver Wrench - For a Gelbin that wants some more healing. Can be paired with Homing Medpacks for full support, or taken on its own for some extra healing.
Khorium Power Core - Not much to say, shifts Shield Projector to quality over quantity.
Backup Batteries - Like Rewind, but you can get it before level 20 and its cooldown can be reduced. I increased the cooldown to make sure it's not too good, but I may have to increase it more.

Tier 6
Elemental Blasting Powder - Damage over time, or healing over time with Homing Medpack.
Blackrock Blasting Powder - More area of effect on damage, or add area to healing.
Saronite Power Core - Spell Armor, potentially at the cost of sanity.
World Shrinker - Invention that shrinks the world, making Gelbin appear larger and stronger. Might need more duration/lower cooldown.

Tier 7
Leystone Matrix - More duration should help in longer fights, and make it harder for the other team to just avoid Gelbin during his ultimate. Also, adding Spell Armor makes him even harder to kill, which is the general idea.
Field Commander - More movement speed, and more traits. Seems fair, if a little unimpressive.
Like Clockwork - A talent that awards a full invention build. Unfortunately, the 6th invention is in the same tier as this talent, but oh well. Sacrificing many powerful talents for a potential 25 Armor at all times seems fair.
Gnomish Jumper Cables - Crazy invention. May be a little too good, especially with Power Wrench. I like the general concept, though.

v1.2
-Updated some descriptions to reflect talent changes
-Replaced Cloaking Field with Energize
-Increased the duration of World Shrinker from 4 to 5 seconds, and updated its description
-Made Homing Chicken immune to spells

v1.1
-Renamed Gnomish Army Knife to Wrench-a-rang
-Changed the 30 Armor of Gnomish Battlesuit to 30 Physical Armor
-Changed the level 20 talent for Gnomish Battlesuit from Adamantite Frame to Leystone Matrix