How to explore the blockchain?

I know that there are many web based cardano explorers out there, but in many cases I find that the features are somewhat limited .

Is there a crash course available that explains what kind of tools are needed for analysing the block chain. I’ve seen that people have have made interesting analysis for example the amount of wallets holding tokens of specific policy etc. Here is one example twitter post from Stale:

I would like to learn more about this. Thanks!

Have you looked at cardano-db-sync?

I just started looking on cardano-graphql, but that SQL approach of db-sync might be a better fit for me.