All the activities calls the PL/SQL procedure:
Compare Date/Compare Number/Compare Text WF_STANDARD.COMPARE
Compare Execution Time Activity
The Block activity lets you pause a process until some external program or manual step completes and makes a call to the CompleteActivity Workflow Engine API.
Defer Thread Activity
The Defer Thread activity defers the subsequent process thread to the background queue without requiring you to change the cost of each activity in that thread to a value above the Workflow Engine threshold.
Launch Process Activity
The Launch Process activity lets you launch another workflow process from the current process.
Loop Counter Activity: