CryptoCurrencyAlerting.com - excellent easy service - get notification about new ICOs, or if your coin goes above/below a certain threshold that you set
multicoincharts.com - very useful interface - view multiple charts side by side in one page
ftx.com - Monitor the chart of any coin, and some stocks. Excellent trading view for technical analysis. You don't have to be logged in to use the charts.
twitter.com - Unfortunately, influencers (like ElonMusk) move the market a lot!
google.com/alerts - get alerts about latest news as Google gets them, by keyword ("SEC Ripple" for example)
youtube.com - NOT a great source. It's mostly people screaming BUY/HODL about the coins that they themselves own. Not usually a reliable way to understand real world sentiment. However, it's a good place to learn about the underlying technology or upcoming projects.
News sites (aggregators)
cryptobriefing.com - easy to read, nice easy summary of the latest few stories (no repeats)
cryptopanic.com - a huge amount of content. Filter news by coin, see chart next to headlines
cryptonews-api.com - for the nerds - build your own app, or integrate this with some other tools