You are a student of spells that modify energy and matter. To you, the world is not a fixed thing, but eminently mutable, and you delight in being an agent of change. You wield the raw stuff of creation and learn to alter both physical forms and mental qualities. Your magic gives you the tools to become a smith on reality's forge, weaving the fabric of reality in ways that are not ephemeral or merely displaced, but real and patiently crafted to last with the devotion of a true craftsman or artist. Some transmuters are tinkerers and pranksters, turning people into toads and transforming copper into silver for fun and occasional profit. Others pursue their magical studies with deadly seriousness, seeking the power of the gods to make and destroy worlds. 

Author's Note: this is an adaptation of the School of Transmutation subclass, to fix some features that were considered underpowered, and to invoke the feeling of an arcane user that builds and creates, rather than just changing or shaping elements of reality.

Transmuter's Focus

You specialise in wielding arcane magics to build upon the very fabric of reality, focusing your skills by crafting and adapting new creations in the material world at an expert level.

Beginning when you select this school at 2nd level, the gold and time you must spend to copy a Transmutation spell into your spellbook is halved.

In addition you gain proficiency in Arcana, unless you are already proficient, in which case you can instead add twice your proficiency bonus to ability checks you make with that skill. Finally, you gain proficiency with one type of artisan's tools of your choice. As you use these tools to shape reality to your arcane will, you may also use them as your spellcasting focus.

Alchemical Savant

Starting at 2nd level when you select this school, you can temporarily alter the physical properties of non magical objects and surfaces, changing them from one substance into another.

You may spend one minute to perform a special alchemical procedure on one medium sized or smaller object, portion of an object, or section of a surface. You must be able to touch this object or surface, and it must be composed entirely of wood, stone (but not a gemstone), or metal (such as steel, copper, iron, silver, etc.). This procedure allows you to transform the material of the object or surface into a different one, or type, of the previously listed materials. This transformation lasts for one hour unless you use your action to end it, at which point the material reverts to its original substance. You can use this ability a number of times equal to your Intelligence bonus (minimum 1), and you regain your expended uses when you complete a long rest.

Artisan's Creation

Starting at 6th level, you can spend 1 hour creating a trinket, or other form of craft using your tool spell casting focus, that stores transmutation magic. You can benefit from the creation yourself or give it to another creature. A creature gains the benefits of your choice as long as the item is in the creature’s possession. When you craft the item, choose a number of benefits, equal to half your proficiency bonus rounded down, from the following options:

• Darkvision out to a range of 60 feet
• An increase to speed of 10 feet while the creature is unencumbered
• Proficiency in Constitution saving throws
• Resistance to acid, cold, fire, lightning, or thunder damage (your choice whenever you choose this benefit)
• Water breathing
• Toughened skin giving a +2 bonus to AC while the creature is not wearing heavy armour.

Each time you cast a transmutation spell, you can change one of the effects of your crafted item, if it is on your person.

If you make a new creation, the previous one ceases to function.

Residual Recycling

Beginning at 10th level, casting transmutation spells comes so easily to you that you can harness and repurpose the excess arcane energy. When you cast a Transmutation spell of 2nd level or higher using a spell slot, you regain one expended spell slot. The slot you regain must be at least one level lower than the spell you cast and can’t be higher than 4th level.

Master Transmuter

Starting at 14th level, you can use your action to consume the reserve of transmutation magic stored within your artisan's creation in a single burst. When you do so, choose one of the following effects. Your creation is destroyed and can’t be remade until you finish a long rest.

Major Transformation. You can transmute one nonmagical object—of a Large size or smaller—into another nonmagical object of similar or smaller size, and of equal or lesser value. You must spend 1 minute handling the object to transform it.

Panacea. You remove all curses, diseases, and poisons affecting a creature that you touch with the artisan's creation. The creature also regains all its hit points.

Restore Life. You cast the Raise Dead spell on a creature you touch with the artisan's creation, without expending a spell slot or needing to have the spell in your spellbook.

Etherealness. As a reaction when an attack would reduce your hit points to 0, before taking the damage, you can cast the Etherealness spell on yourself without expending a spell slot.

Pure Transmutation. Cast any Transmutation spell of 5th level or lower without expending a spell slot. It does not need to be a spell from your spellbook, nor does it need to be from the Wizard spell list.

Creation. When using a creation transmutation spell, like Create Homunculus or Clone, then your artisan's creation can be used for all required material components.