They make great borders for flower beds if you have an English garden type landscaping , you can also seel them to people wanting to add brick or replace old damaged brick. Where did you remove them from maybe so pics of your house and lot would help .

Flower bed borders is my suggestion. Not arranged flat, but on edge instead.

@Patricia Colwell Consulting - They came out of an old building I purchased. I built a coffee shop on the first floor after gutting it. The chimney ran through both stories, but It was just used for furnace ventilation. There was never a fireplace in here.

@Little Bug - Great idea....laying on the edge instead of flat. Thank you.

I like this idea, too: