I'd arrange meetings with colleagues in other teams and departments to find out what problems they are working on and how you might help. If they have nothing,

I'd arrange meetings with colleagues in other teams and departments to find out what problems they are working on and how you might help. If they have nothing, you could arrange to shadow them for a few hours or half a day. This way you'll find new things to work on, or have a greater understanding of the business and have a larger internal network. Alternatively, if there are ways the business could be improved, you could work on a proposal, and get buy-in and ideas from your colleagues and finally present it to your management.