Bitcoin:
https://aantonop.com/ - Probably the best Resource for Bitcoin
https://www.lopp.net/ - Bitcoin Expert & Resources
http://adam3.us/ - Applied Cryptographer, Inventor Hashcash, Comp Sci PhD Distributed Systems
https://blockstream.com/ - Global leader in Bitcoin & Blockchain technology
http://unenumerated.blogspot.com/ - Nick Szabo - Blockchain, cryptocurrency, and smart contracts pioneer
https://100trillionusd.github.io/ - Focused on bitcoin Stock-to-Flow (S2F) model
https://www.advancingbitcoin.com/videos/ - Exploring all aspects of Bitcoin Development
https://woobull.com/ - In depth information and forecasts on price models, signalling & network etc
Ethereum:
https://vitalik.ca/categories/blockchains.html - Founder of Ethereum
https://extropy.io/ - Consultancy in Distributed Ledger Technology and Cryptography
https://workonblockchain.com/ - Blockchain Events and Education for Developers
Defi:
https://consensys.net/blockchain-use-cases/decentralized-finance/ - Complete guide to the exciting new world of DeFi
https://blog.coinbase.com/a-beginners-guide-to-decentralized-finance-defi-574c68ff43c4 - Guide to DeFi
https://linktr.ee/ChrisBlec - DeFi research, analysis & education
https://defipulse.com/ - Analytics & Rankings of Defi Protocols
Cardano:
https://iohk.io/en/projects/cardano/ - Cardano is a blockchain platform with more advanced features than any protocol yet developed
EOS:
https://block.one/ - Technology and products that enable trust in transactions, transparency in systems, and efficiency in how our world works
Blockchain Oracles - Third-party services that provide smart contracts with external information. They serve as bridges between blockchains and the outside world:
https://academy.binance.com/en/articles/blockchain-oracles-explained
https://chain.link/ - Chainlink's decentralized oracle network provides reliable, tamper-proof inputs and outputs for complex smart contracts on any blockchain
https://bandprotocol.com/ - Band Protocol is a cross-chain data oracle platform that aggregates and connects real-world data and APIs to smart contracts
https://bridge.link/ - Due to the nature of blockchain systems, they are not able to access real world data. Bridge oracle system is a technology through which external data can be injected
Mining:
https://blockoperations.com/ - Mining expert and resources
https://boxmining.com/ - Mining News, Info & Events
https://cryptomining-blog.com/ - Mining Blog
https://www.upstreamdata.ca/ - Interestingly, these guys specialise in mining via wasted energy from oil & gas producers