It's very hard achieve a profit with altcoins. I have taken some "suggested coins" from this topic
https://bitcointalk.org/index.php?topic=2106360.0 "The next 100x or 1000x coin",
(where people trying to guess/suggest the coin that could receive a big pump during end of 2017 early 2018)

At December 2017, it means after 3 years, I get following results:
13,18% Reported a positive evaluation.
10.83% Reported a 0 (total loss)
the others just negative results (prices go down).

(full post here https://www.publish0x.com/bitbollo-cryptocurrencies-blog/a-depth-analysis-of-bitcointalkorg-speculation-thread-the-ne-xpnnjwq )

Despite the market has not been bullish, most of crypto have realized a negative profit, and positive results have been seen just after years of "holding". I think it's very hard find a new gem, this is why generally I continue to buy just bitcoin.