Etherscan is a useful tool for exploring the Ethereum blockchain. You can find information about wallets on there, see your holdings and their value, and find information about token contracts.
To see information about a wallet, including your own wallet, simply copy and paste the public address into the search bar.
To find out information about a token like its contract address (useful for adding tokens to your wallet), type the name of the token in the search bar.
You can also see a lot of other interesting information from pending transactions (useful to get an idea of why a transaction might be taking a while to process) to top accounts (which is interesting to look at if nothing else).
"Etherscan" contains information about the following Cryptocurrencies: