You need to find the right cryptocurrency or token;) There are always opportunities around to make good investments, if you know, where to look for them... I believe certain many altcoins have a good potential to gain 10-20x, maybe even 100x. Hard to imagine bitcoin gaining 10-20x other than very long term - but a very big maybe. But, for all projects: Do your research, because there are very good ones, but very bad ones too! There is no shortcut to your own work! Don't trust the ICO ratings because they can be bought, and don't trust the most visible projects because it just depend on marketing spend, not on the quality of the project! Look at the substance, the business case, the value of the space they are claiming to take over or "disrupt", the nature of tech to be developed, the business experience of the team (most teams don't have a clue of the underlying business!!! so they can't disrupt anything...)
Recently, I have been following in particular Stellar and Stellar-related tokens. Stellar is on the rise because of the prospective Coinbase listing - probably one of the best bets for 2018. Up by more than 50% from the level a week ago, and it will continue for sure. Price has potential to multiply! Worth looking into tokens issued on the Stellar platform that will also profit from the new rise of Stellar...
There, I found an interesting, solid project, experienced people, with their token issued on the Stellar blockchain: AXU of
argentas.io. They seem to have ANN for their community-oriented presale too
https://bitcointalksearch.org/topic/xxx-4431900 Financial blockchain, solid idea & white paper, thinking of putting in some. Just too low profile so far, but it definitely is a hidden gem in my opinion.
Of course one has to diversify between tokens, not to put the eggs in one basket, but this one looks to be worth the risk with a very attractive presale price of 0.4 XLM for 1 AXU that is 50% less than their ICO price later, so this 2x gain together with the underlying Stellar price going up, giving a double boost to it, looks to be like a sure winner, gains soon in pocket I believe - and may soon be 5-10x the initial presale price, later on maybe 20x. Following some EOS related projects too along with other Stellar projects, maybe finding some further ones there too. But I am definitely for AXU as an undiscovered diamond - others I like are much more well known - so far... But I like to pick my own things that the others still ignore - I have gained very nicely that way so far