https://coinmarketcap.com/
Coin market is a great website. You can click on each coin and then they have a link to their website where usually they publish a white paper on their coin. These white papers help readers learn all about the coin, what they are trying to do, and helps you decide if it's something you want to invest in or not.

I also do analysis on the white papers of coins. For example, here is my analysis on Ripple (XRP).

https://steemit.com/xrp/@romorc/an-analysis-of-xrp-fundamentals-for-the-average-joe

I am new to steemit, but I will be doing lots more of these. Please follow if you would like to be kept updated on alt coins out there.