One place where gas is flared off is landfills. Methane is produced by anaerobic decay and must be burned to reduce its climate impact.
One unfortunate consequence of this is bird injury, particularly raptors. They like to perch on the flare stack, and when it flares to life... if they are lucky, only their feathers are damaged and they can be rehabbed. This can probably be ameliorated by design of the stack to avoid perching, but that isn't always done.
I know biogas digesters exist, but I am unfamiliar with the economics of such systems. It seems like a better way to deal with the methane than flaring it off, but cheap natural gas in the US might make it uneconomical to do so. I’d be curious if anyone has any insight into that.
People have looked at microturbines to burn landfill gas. It's not something one could just put into a natural gas pipeline as it's about 1/2 CO2. Even in microturbines it requires cleanup because of cosmetics. In a landfill, cosmetics decay to produce volatile organosilicon compounds, and when these burn they deposit silicon dioxide slag on turbine components.