Is there a way to have multiple triggers for a single workflow?

[Felipe]

You could maybe have different workflows with different triggers that call your target/main workflow 

[jacolei]

Absolutely, you would design a trigger for one task (eg new file) and another one (eg schedule), then have a third task that runs when both of those tasks complete

[mhiltner]

You could have a workflow with two tasks, one being a "trigger checker" that could be a super light task scheduled to run every X hours/minutes. This first task would check for your different triggers and define a success criteria for your next task. Then you condition the actual task that you need to execute only if one of these conditions are satisfied.