After playing around with an Alchemist, I felt that there wasn't much in the subclass that made playing it feel unique when compared with other Artificer subclasses.  So, I set out to tweak the main subclass feature to make it feel more... Alchemist-y, for lack of a better term.

I did this as an item, but making it a class feature variant might also work.  The main goals were:

• make the Alchemist create something (as per the design philosophy for all Artificer subclasses).
• make the Alchemist able to benefit others directly, similar to the official subclass.
• give the Alchemist (and potentially others) some bonus action economy that is unique to them.
• emphasize the more caster-oriented focus of the Alchemist, using Cantrip-like effects.
• emphasize versatility of use and area-control potential.
• grant some longevity for expending spell slots to create elixirs, though not as long-lasting as other Artificer subclasses.

"Alchemical Journal"

• Rare, requires attunement by an Alchemist
  
• Flavour text: "A journal detailing a famous alchemist' experiments with highly reactive chemicals. The edges of the cover and pages either appear burned, corroded or melted..."

Usage

• After you finish a long rest, this item can be used to create two Reactive Elixirs, as listed below. They only remain potent for one day.
  • Reactive Elixirs can either be Consumed or Thrown using an Action.
  • If their effects prompt a saving throw, it uses your Spell Save DC modifier, regardless of who caused the effect.
  • Their effects prompt a saving throw when an Area-of-Effect first appears, when a creature moves into it for the first time on a turn, or when they end their turn within it.  
• You may choose to use your Experimental Elixirs subclass feature to produce Reactive Elixirs, selecting which one to produce.
  • Your Alchemical Savant subclass feature applies to the damage of Reactive Elixirs, but only when you personally use them with the Consumed effect.

Reactive Elixir Options

• "Dissolution", lasts for 30 seconds:
  • Consumed: as a Bonus Action, you spray acid in a 15 foot cone in front of you.
  • Thrown: for the duration, acid coats the ground in a 15 foot square, centered at the point of impact.
    • Every 5 seconds, one side of the square grows by 5 feet (you pick which side).
      • All targets within the area make a Dexterity save or take 2d4 Acid damage (4d4 at Level 10 or higher).
• "Conflagration", lasts for 30 seconds:
  • Consumed: as a Bonus Action, you hurl a mote of fire up to 40 feet away, which erupts in a 5 foot radius.
  • Thrown: for the duration, flames erupt from the point of impact and then extend up to 15 feet along the ground towards you, stopping if they reach you.
    • Each turn, the flames extend up to 15 feet along the ground towards you, stopping if they reach you.
      • All targets make a Dexterity save or takes 1d8 Fire damage (2d8 at Level 10 or higher).
• "Decomposition", lasts for 30 seconds:
  • Consumed: as a Bonus Action, you exhale necrotic mist in a 30 foot line in front of you.
  • Thrown: for the duration, a cloud of necrotic mist with a 10 foot radius manifests at the point of impact.
    • Each turn, you can move the cloud up to 20 feet in one direction as a Free Action.
      • All targets within the area make a Constitution save or take 1d8 Necrotic damage (2d8 at Level 10 or higher).
• "Infection", lasts for 30 seconds:
  • Consumed: as a Bonus Action, you cause poison gas to erupt in a 10 foot radius around you.
  • Thrown: for the duration, a ring of poison gas with a 15 foot radius manifests at the point of impact, centered around a 5 foot "dead zone".
    • Each turn, the radius of both the ring and the "dead zone" increases by 5 feet.
      • All targets make a Constitution save or take 1d10 Poison damage (2d10 at Level 10 or higher).

All comments welcome!