Blockchair is a blockchain search and analytics engine for Bitcoin, Ethereum, Bitcoin Cash, Litecoin, Bitcoin SV, Dash, Ripple, Dogecoin and Groestlcoin or you can also say it's an engine that consists of blockchain explorers on steroids. You can filter and sort blocks, transactions, and their content by a variety of different criteria, as well as perform full-text search over the blockchains.
Blockchair provides insight to blockchain coin metrics on the data level, so called a "blockchain explorer". Useful data to quantize the health of a blockchain network, coin or future.