Blockchain - Bitcoin Block Explorer - Blockchain is popular Bitcoin Legacy (BTC) block explorer.
Blockchair - Bitcoin, BitcoinCash, Ethereum, and Litecoin blockchain search and analytics engine.
Bitcoin.com Explorer - View transactions, addresses, and more on the Bitcoin Cash and Bitcoin Core blockchains.
Etherscan - Etherscan China allows you to explore and search the Ethereum blockchain for transactions, addresses, tokens, prices and other activities taking place on Ethereum (ETH)
BitRef - View the current balance of any Bitcoin address.
BeMoreBitcoin Bitcoin Wallet LookUp - The bitcoin wallet address checker allows you to quickly check a wallet address, returning the amount held in the wallet and recent transaction details.