Minimum and maximum values of "all" cryptocurrencies? I can't find a "cryptocurrency" stack exchange, and I have a question that spans all cryptocurrencies, in particular, how to handle them programatically - one database column to rule them "all"!

I say "all", because it's becoming super-hard to keep track of them all, so I don't expect anybody to know the whole story.

So, we want to store an amount in the database - the implication for BTC is that we should store values from 1e-8 to 1e8 - but what about other cryptocurrencies?

I'm looking for a value which would be enough for all of the current mainstream coins, and if possible (fingers crossed!) a rationale why that value would be enough for at least 90% of any future currencies that might appear?
I can't answer for all cryptocurrencies, but for bitcoin, you shoud store values as long and not doubles. The unit of account of bitcoin is the satoshi, a hundred millionth of Bitcoin. Since there can only be 21M BTC ever, that's a maximum of 2.1 quadrillion (2.1 * 10^5) satoshis. That number fits in 64 bits.

For Ethereum, you need 256 bits unsigned integers IIRC.