The Football Association have issued five charges relating to breaches of the organisation's Football Agents Regulations.
Four separate investigations have contributed to the charges being levelled, with a variety of breaches alleged.
Leeds have been charged with using an unlicensed agent - Lorenzo Paolo - over the signing of Anthony Elding from Stockport in January, while Millwall player Ali Fuseini has been charged with failing to ensure the exclusivity of representation.
Fuseini allegedly consented to representation from one agent while already under contract with another.
Both Leeds and Fuseini have until September 3 to respond to the allegations.
Crystal Palace and agent Faisal Kashmiri have been charged with breaching FA rules over the transfer of Nick Carle from Bristol City.
Regulations prohibit agents from acting for two different clubs in consecutive deals involving the same player, and clubs are not allowed to use any agent involved in those circumstances.
Kashmiri has admitted he acted in relation to the player's move to Ashton Gate and has requested a personal hearing. Palace, who have also pleaded guilty, have requested a non-personal hearing.
Agent Paul Wells has been charged with entering into a representation contract with a player under 16 years old and has until September 4 to respond.