Different types of Cross shapes significance? What is signified by different kinds of crosses? For example some graves have club(cards game) leaves type edges crosses, some graves have simple crosses?
I think you are referring to the Budded Cross.



The article says, 


  A cross with three circles or discs on each arm in a Christian context
  represents the Holy Trinity but was probably also copied from earlier
  Celtic Druidry, where the circles or rings represent the three
  dominions of earth, sky and sea.
  
  There are several names for this cross, depending on the
  interpretation. These include Budded, Apostles', or Cathedral Cross,
  all implying a religious theme, and Treflée or Botonée1 in a heraldic
  context.


And the Christian Cross, the best-known religious symbol of Christianity.



More crosses here on Wikipedia