A mini made for a homebrewed artificer subclass. Below is all of the info needed to run this subclass in your own game!

Surveyor Subclass

Tool Proficiency:
When you adopt this specialization at 3rd level, you gain proficiency with cartographer tools. If you already have this proficiency, you gain proficiency with one other type of artisan's tools of your choice.

Surveyor Spells:
Starting at 3rd level, you always have certain spells prepared after you reach particular levels in this class, as shown in the Surveyor Spells table. These spells count as artificer spells for you, but they don’t count against the number of artificer spells you prepare.

3rd (1st lv) Hunter's Mark, Shield
5th (2nd lv) Pass Without a Trace, Locate Object
9th (3rd lv) Thunder Step, Galder's Tower
13th (4th lv) Hallucinatory Terrain, Dominate Beast
17th (5th lv) Teleportation Circle, Commune With Nature

Thopter

By 3rd level, your tinkering has borne you a faithful companion, a Thopter. It's friendly to you and your companions, and it obeys your commands. See its game statistics in the Thopter stat block, which uses your proficiency bonus (PB) in several places.
In combat, the Thopter shares your initiative count, but it takes its turn immediately after yours. It can move on its own, but the only action it takes on its turn is the Dodge action, unless you take a bonus action on your turn to command it to take another action. That action can be one in its stat block or some other action. (Dash, Dodge, Disengage, Hide, Help, Interact) If you are incapacitated, the Thopter can take any action of its choice, not just Dodge.

If the Mending spell is cast on it, it regains 1d6+int+pb hit points. If it has died you can use your cartographer Tools as an action to revive it you Must Be within 30 Ft. and you expend a spell slot of 1st level or higher.

Both during and outside of Combat, While your Thopter is within 100 feet of you, you can communicate with it telepathically. Additionally, as an action, you can see through your Thopter’s Lens and hear what it hears until the start of your next turn, gaining the benefits of any special senses that the Thopter has. During this time, you are deaf and blind with regard to your own senses.

The Thopter can Carry up to 5 Lbs on a small Hook attached to the bottom of the Thopter
At the end of a long rest, you can create a new Thopter if you have cartographer Tools with you. If you already have a Thopter from this feature, the first one immediately perishes, Unless you can control more than one then you may have a number of them at a time equal to the number you can control. The Thopter(s) also perishes if you die.

Thopter (Small Construct)

AC 11
HP 1+ Your INT Mod + 2 Times Artificer Level
Speed 40 ft Fly, 0 Walk Speed, 0 Swim Speed
Str 8 (-1) Dmg Immunity: Poison
Dex 14 (+2) Condition Immunity: Charmed, Exhausted, Poisoned
Con 10 (0)
INT 4 (-3) Languages: Understands all languages you Speak but cannot Speak
Wis 10 (0)
Cha 6 (-2)

Abilites__

Flyby-The Thopter doesn't provoke opportunity attacks when it flies out of an enemy's reach.

Actions__

Light- While the Light is on the Thopter Emits a mid level Bright Light. While the light is on the Thopter has Disadvantage on Stealth Checks.

Smack- Melee Weapon Attack: +PB to Hit, Reach 5 Ft, One Target 1d4+Your INT Bludgeoning Damage

Crash- The Thopter Hurls itself into Target. This Action Destroys the Thopter. Roll 1d20 + your INT + PB to hit. It deals 1d10 + your INT Mod + The Remaining Thopter Health in Bludgeoning Damage.

At 5th Level Extensive time with your Thopter has Led you to modify it. You may Apply 1 of the Thopter Augments to your Thopter. You may change your Augments During a long rest.

At 9th Level Your skills with Thopter Piloting has Blessed you with the ability to control 2 Thopters at a time. They can both be commanded on the same Bonus Action. They can also Have Seperate Augments, Unless the Augment you choose requires 2 Thopters.

At 15th Level You Can now Control 3 Thopters at a time. They can all be commanded on the same Bonus Action. They can also Have Seperate Augments, Unless the Augment you choose requires 2 or 3 Thopters.

Also Thopters can now have 2 Augments Each.

(Thopters in the conjoined status can have separate augments that apply to the conjoined Thopter as one unit. [Ask DM] )

___Thopter Augment List____

Submersible- Thopters you control can be Piloted underwater and gain a swim speed of 40 Ft

Blades- Thopters you control have sharp blades and their Smack Attack gets replaced with a slash ability-Melee Weapon Attack: +PB to Hit, Reach 5 Ft, One Target, 1d6+Your INT Slashing Damage

Claw- Thopters can now Carry and Move up to 25 Lbs instead of its normal 5 Lbs

Connectivity- Thopters can be Commanded and viewed Through up to 250 Feet away instead of 100

Self repair subroutine- Thopters with this augment can spend an action to heal themselves for 1d6+your int mod

Flight pegs- Thopters with this augment have pegs on the side of them allowing you to hook your special made boots into them. While Hooked you have a fly speed of 20 and cannot be knocked from the thopter. The thopter can be Targets separately from you. While Flying the Thopters cannot make Melee Attack Actions or Bonus Actions.

Silent Movement- The Thopters now move silently and now have ADV on Stealth Checks

Speed Thruster- the Thopters can now Dash as a Bonus Action

Fitted Crossbow- The Thopters Gets a Mounted Crossbow that will give the Thopter a Ranged Attack Called Ping-Ranged Weapon Attack: +PB to Hit, Range 20/100 Ft, One Target, 1d6+Your INT Piercing Damage

Darkvision Lens- The Thopters gets Outfitted with a Night Vision Lens and no longer needs its light to have darkvision.

Spell Transfer Sigil- the Thopters get infused with a Spell Sigil allowing you to cast any Touch spell Through the Thopter. (this cannot be done in addition to a Thopter Attack it is done as its own action)

Drill-The Thopters gain a burrow speed of 30.

Spot Light- While the Light is on You Gain adv on Investigation Checks

Search and Rescue- Thopters with this Augment can touch a Target and give them 1d4+your int temporary hp. When this is used the Thopter takes the 1d4 rolled earlier in damage.

Heavily Armored- Heavy Plating is Applied to the Thopter Giving it an AC of 15 Total and reduces its speed to 30 Fly (and all other movement additions)

Boot Hooks- (Prerequisite Artificer LV9) You can now Hook Your Boots into Special Made Hooks on the Back of Two of your Thopters. While Hooked you gain a Fly Speed of 30. Thopters Being used For Flight cannot take any Melee Attack Actions or Bonus Actions. You Cannot Be Knocked off the Thopters. The Thopters Can Still Be Targeted Independently from you.This Ability does NOT change the Thopters carry weight. They cannot Carry anything in Addition to you and your things. Boots can be Hooked as a Bonus Action.

Net Attachment- (Prerequisite Artificer LV9) Using 2 Thopters they can Carry a net and Drop a net onto a Target. Use the Net Stat Block For Attack Rules.

Conjoined Thopters- (Prerequisite Artificer LV9) A pole is Welded Between Two Thopters The Distance Between the Thopters is a total of 5 ft. The Thopters move and Attack as 1 Doubling all Damage from the Conjoined Thopters. Carry Weight & Health are doubled. Reviving the Thopters takes 2 LV 1 Spell Slots or 1 LV2 Spell Slot. They also Gain a Trip Action: DC Spell Save Dex or Str Save (Targets Choice) or Be knocked Prone.

Improved Blades- (Prerequisite Artificer LV9)Thopters you control have sharp blades and their Smack Attack gets replaced with a slash ability-Melee Weapon Attack: +PB to Hit, Reach 5 Ft, One Target, 1d8+Your INT Slashing Damage

Improved Fitted Crossbow-(Prerequisite Artificer LV9) The Thopters Gets a Mounted Crossbow that will give the Thopter a Ranged Attack Called Ping-Ranged Weapon Attack: +PB to Hit, Range 20/100 Ft, One Target, 1d8+Your INT Piercing Damage

Elemental Whip- (Prerequisite LV9) When choosing this Augment Choose and Elemental Damage Type. Thopters with this Augment Gain an Attack Called Elemental Whip Melee Weapon Attack, Range 10 ft, One Target, 1d8+Your INT in Chosen Elemental DMG

Stealth Surveyors- (Prerequisite Artificer LV9) Thopters with this ability can turn Invisible a Number of Times, equal to your Prof Bonus, Per Day. Thopters in this state follow the same rules as an invisible player as if they cast the invisibility spell.

Sleek Design- (Prerequisite Artificer LV9) Improving on the Design of the Thopters You can add +10 to any Speed the Thopter With this ability has. (This ability Can Also Increase your Fly Speed while using the Boot Hook Augment)

Thopter Bomber- (Prerequisite Artificer LV9) Thopters with this ability have a compartment that can carry an item, no bigger than the size of your hand, within it as an action the Thopter can Drop this Item. Once Dropped if the item needs a trigger it is already triggered once released. (Examples: A stick of Dynamite can be stored and dropped from the Thopter Once dropped it is already lit; A potion can Be Dropped to Allies, Pouch of Coins to Pay ransoms; ETC)

Improved Search and Rescue- (Prerequisite lv9) Thopters with this Augment can touch a Target and give them 1d6+your int temporary hp. When this is used the Thopter takes the 1d6 rolled earlier in damage.

Swarm- (Prerequisite Artificer 15) Using 3 Thopters they can be augmented to have Extremely Evasive Movement Patterns. The Thopters gain a New Swarm Action: DC Spell Save Wis Save on a fail the Target Cannot Focus on combat and must swat at the thopters the creature is considered stunned. Thopters gain AC equal to your INT + Your PB During this Action. The Thopters Swarm and Fly all around target Creature Attempting To Distract it and Waste its Turn.

Marked Location- (Prerequisite Artificer 15) Thopters with this Ability Can Mark A Creatures Weak spot giving the Next Attack ADV on Target Creature

Controlled Explosives- (Prerequisite Artificer 15) The Crash Ability Now Leaves the Thopters With This Augment at 1 HP after a crash.

Optimized Search and Rescue- (Prerequisite lv15) Thopters with this Augment can touch a Target and give them 1d8+your int temporary hp. When this is used the Thopter takes the 1d8 rolled earlier in damage.

Optimized Blades- (Prerequisite Artificer LV15)Thopters you control have sharp blades and their Smack Attack gets replaced with a slash ability-Melee Weapon Attack: +PB to Hit, Reach 5 Ft, One Target, 1d10+Your INT Slashing Damage

Optimized Fitted Crossbow-(Prerequisite Artificer LV15) The Thopters Gets a Mounted Crossbow that will give the Thopter a Ranged Attack Called Ping-Ranged Weapon Attack: +PB to Hit, Range 20/100 Ft, One Target, 1d10+Your INT Piercing Damage

Optimized Elemental Whip- (Prerequisite LV15) When choosing this Augment Choose and Elemental Damage Type. Thopters with this Augment Gain an Attack Called Elemental Whip Melee Weapon Attack, Range 10 ft, One Target, 1d10+Your INT in Chosen Elemental DMG

Conjoined Tri Drone- (Prerequisite Artificer lv15) 3 thopters are conjoined in a triangle formation with a platform between them. Their dimensions are 3 5 foot sides. The Thopters move and Attack as 1 Tripling all Damage from the Conjoined Thopters. Carry Weight and Health are Tripled. Any Creature Medium or Smaller may ride on top of the platform without altering its speed (This does Not change the amount of weight the Thopters can carry) While flying passengers The Tri Drone cannot make Melee Attack Actions or Bonus Actions. The Conjoined Thopter may be targeted separately from its passengers, but each individual Thopter cannot be singled out. Reviving the Thopters takes 3 LV 1 Spell Slots or 1 LV3 Spell Slot. They also Gain a-
Trip Action: DC Spell Save Dex or Str Save (Targets Choice) or Be knocked Prone.