Tools like AmmoSeek allow searching for reloading components or full cartridges with terms like "lead-free".
If you're seeking eclectic projectiles, like subsonic capabilities, see the following manufacturers:
Here is a helpful list of manufacturers' lead-free ammunition options. Many manufacturers will also describe their lead-free products and ballistic data on the company website.
This bullet performance review by Hunting with Non-Lead provides excellent overview of terminal performance from modern non-toxic projectiles.
Poisoned Wildlife and Tainted Meat: Why Hunters Are Moving Away From Lead Bullets, Many hunters are ditching traditional ammunition amid mounting evidence that it harms scavengers and pollutes the food people eat. (New York Times, 2018)
Nearly Half of US Bald Eagles Suffer Lead Poisoning, Researchers report harmful levels of toxic lead were found in the bones of 46% of bald eagles sampled in 38 states. (Associated Press, 2022)
Non-Lead Hunter, Documentary by Anthony Prieto