I think market cycles are worth mentioning. These cycles are driven by halving. Around the same time, a long BTC uptrend begins. After some time, the growth of many altcoins begins. That was two times. It can start again in a year, since the halving is expected in the first half of 2020. On the other hand, the conditions are changing, and the cryptocurrency market may behave differently in the future.

I usually use CMC. But if I need to check a specific asset, I look at the exchanges where this asset is listed.