Dockside Extortionist Combos

Dockside Extortionist can be used with cards like Voldaren Epicure that have enter the battlefield effects to create an infinite loop. In the case of Voldaren Epicure, you would deal 1 damage to each opponent an infinite amount of times. As long as Cloudstone Curio is on the battlefield when you cast Dockside Extortionist, you can return another creature to your hand with an Enters the Battlefield effect, and then re-cast that creature to get it's effect and return Dockside Extortionist to your hand. This requires your opponents to have enough Artifacts and/or Enchantments to equal the combined Mana Values or Dockside Extortionist and the other creature you are using with EtB effects (usually 3 or 4).

As long as your opponents control a combined 5 or more Artifacts and/or Enchantments, you can use Temur Sabertooth to return Dockside Extortionist to your hand and re-cast using 4 of the Treasure tokens that you create each time. This will allow you to create infinite Treasure tokens.

This is one of the most mana heavy options to use with Dockside Extortionist, as it requires your opponents to control at least a combined 9 Artifacts and/or Enchantments to create infinite Treasure Tokens. Once you have created infinite Mana, you can then use Capsize to clear all permanents from your opponent's board.

With this one you just need your opponent's to control 4 Artifacts and/or Enchantments between them. So you can activate Emiel the Blessed's  ability over and over to keep flickering Dockside Extortionist until you generate infinite treasure.