Hydra bones

Hydra Bones is a members-only item on the OSRS Grand Exchange in the other category.

In-game examine text: "The bones of a hydra."

It has a Grand Exchange buy limit of 7,500 every four hours, a high alchemy value of 96 gp, and item ID 22786.

View on OSRS Wiki

Hydra Bones shows an active flip setup with a margin of +13 gp and 136,613 trades over the last 24 hours.

At the buy limit of 7,500 every four hours, max profit per cycle is about 97.5k gp — high margin with healthy liquidity.