what is nft-fossils fr?

nft-fossils is a command line tool for finding NFTs that once sold for tens or hundreds of thousands of dollars during the crypto boom and are now listed for a tiny fraction of that price. It works in two steps. First, it builds or downloads an index that records which NFT tokens had large historical sales, backed by the actual on-chain transaction as proof, so those numbers cannot be faked after the fact. Second, when you run a search, it checks OpenSea for the current listing price of those tokens, so the prices you see are always live rather than pulled from a stale database. You can filter results by minimum historical sale amount, maximum current price, how many separate big sales a token had, how far the price has dropped from its peak, and the date range of the original sale. Results can be printed as a table, or written out as a CSV or JSON file. Building a full index from scratch takes about a day and needs OpenSea and Alchemy API keys, but a prebuilt index ships with each release so most people can get results in seconds, and an update command refreshes an existing index quickly instead of rebuilding it. The README is careful about honesty limits. It only counts sales from OpenSea and Blur, not other marketplaces. It filters out bundle sales where several NFTs sold together for one price, since attributing the full amount to each token would be misleading. It only supports ERC-721 tokens, not the ERC-1155 standard, since those exist in multiple copies. The author is explicit that this is not financial advice, and that these tokens are cheap because demand for them has disappeared, not because they are secretly undervalued. The tool has no external Python dependencies and works with any Python 3.9 or newer. It is released under the MIT license.