I don't know of any TLO's that return your current tasks, but there are ways to find out regardless.
1. Do a simple /tasktimer, use events to catch the output and a bit of logic to calculate whether or not you have a task.
2. Let MQ read your task window.
Here's a simple example how to read a specifik line in your task list (which I've used in other regards):
${Window[TaskWnd].Child[TASK_TaskList].List[1,2]}
That line will return the task name of the very fast task in your task window. If you have no task it will not return anything.
Note that the task window must be open for this info to be read.