Price/Volume Data (Primarily) 

Bitcoin Charts
Bitcoinity
Coin 360 (great visualizations)
Coin Library
​Coin Gecko
​Coin Market Cap
Coin Metrics (Historical data downloads!)
Cryptocurrency Market
Crypto Compare
Dapp Radar (Focus on DeFI and NFT)
​Live Coin Watch
On Chain FX

Blockchain Data

0x Tracker
Bitforce 5
Bloxy
Blockchain
​Block Chair
​Block Path
​Etherscan

Other Data

Are we decentralized yet? (multiple measures)
​Bit Info Charts (coin profiles)
Bit Nodes (Bitcoin nodes)
Bitcoin Energy Consumption
CCAF (aggregate market/company profile)
​Coin Dance (coin network profiles)
Coin Map (Crypto ATM locations)
CRIX
CryptoGovernance (Project examining governance)
DeFI Prime (DeFI Project Profiles)
DeFI Pulse
Dune Analytics (community dashboards)
Elementus (ICO boom, ends in 2018)
Messari (has price and volume data, but also incredibly detailed info on each coin)
Realtime Bitcoin Globe (Spinning globe showing BTC transactions)
Transaction Fee Info