If you are looking for coins with really high volatiliy then you just need to go to coinmarketcap.com and start looking at the project that are listed on rank 1000 or lower in terms of  marketcap. Those projects usually fluctuate a lot price wise, but i don't really think that most of them are suitable for daytrading because usually they also have a pretty low trading volume and if you want to trade with big amounts then the impact of your own trades is to big. I generally would not look for coins with high volatiliy because in the crypto space almost every coin fluctuates enough to do daytrading.