Alchemists are people who practice alchemy, a form of chemistry and speculative philosophy which is concerned with discovering methods for transmuting base metals into gold and with finding a universal solvent and an Elixir of Immortality.
The only card with the subtype Alchemist was Samite Alchemist. This was changed to Cleric in the Grand Creature Type Update. Battletide Alchemist was also printed as a Cleric, Aphetto Alchemist and Sedraxis Alchemist were printed as Wizards and Cho-Arrim Alchemist as Spellshaper. None of these cards had top-down design reflecting transmuting skills.