A jack of all trades
Definition 1 of 1
Pro Tip 1/3Versatile Implication
Implies capability in many areas but not necessarily expertise. 
Even as a jack of all trades, Tom struggles to find what he's truly best at.
Pro Tip 2/3Often Incomplete
Commonly used with 'master of none' to emphasize lack of mastery. 
Yes, he's a jack of all trades, but master of none, unfortunately.
Pro Tip 3/3Non-specialist
Suggests being generalist rather than a specialist in any field. 
Our team needs a jack of all trades to handle diverse tasks.