Here is a simple, yet effective approach. It is a modification of the Steem logo to incorporate a lightning bolt. I'm using the same colors and typography of the original logo, however, that can be easily changed if you're looking to separate yourself a little more from the Steem brand.

https://drive.google.com/open?id=1NTvAp0OOUSIM-_F4NXjiXsuvvnMIRu62