Here are a few of the most popular Blockchain-Explorers:

• Bitcoin:
  • Blockchain Explorer
• Ethereum:
  • Etherscan.io
• Cardano ADA:
  • Explorer.cardano.org
• XRP Ripple:
  • livenet.xrpl.org
• XRPL ODL Rosetta:
  • threexrp.dev
• Stellar XLM:
  • Stellar Network-activity