-- some of them have a particular focus.... so bear that in mind, that focus can also be a bias so to speak.
Vitalik for Ethereum.
Dan Larimer the Steem/Bitshares/EOS co founder for lots of things for those angles he has @dan and @dantheman accounts here
There is a guy in Canadastan here named Francis Pouliot -- he is a genius too, for lots of stuff, mostly BTC.
That will get you started.