How to find good altcoins that might x10-x100 returns after some weeks/months or short-term? I think investments in Btc, Eth should be for long-term, not for short-term. Thank you very much.
bitcoin can both be a short term and long term investment although the long is easier to make profit of.
ethereum should not even be an investment for at least a couple of months until it crashes properly without the artificial upkeeping the price and then think about investing in it when it really bottoms out if it still were alive.
for other altcoins look in LTC, it has something big coming on Aug 1 and also there are a lot of good news about it. apart from that, it is like the only altcoin that didn't fall and it still is worth the same as before 0.019
BTCif you want a 100x rise then find smaller altcoins that have not yet been pumped. look at their price history for that.
don't bother with market cap it is useless.
instead look at the previous weeks daily volume and price and try to find signs of accumulation and see if it has changed compared to the weeks before. if you found "the signs" then invest.