TradingView's my number one at the moment. Lots of indicators built in and plenty more from the community, you're able to see other peoples' charts easily if that's your thing, and the site's generally smooth and good-looking as well, with plenty of tools for charting. I also sometimes use
Bitcoinwisdom.io for charting, though the site's much more basic than TradingView and there's less customizeability overall, with just a few basic but very useful customizeable indicators available. The site's also easy to load on almost any system.
When I trade on leverage,
Antiliquidation.com is one of my favorite tools. The site helps you set an appropriate position size for the stops and targets you set, while also noting how much of your capital you're willing to risk. There's also a neat calculator to determine your liquidation price and how much of your money's going to the insurance fund in the case of Bitmex in case you get liquidated.