A list of websites and tools I find super useful to my workflow both in and out of makecode
*note that certain websites and tools may become out of date or new ones might make its way onto the list, so make sure to scroll down to check the rest of the topic!
Also they’re all free! 
PSG Digital Art Tutorial
Excellent tutorial for digital art in general, just amazing tips and advice from someone with digital art mastery. It’s not specifically pixel art, but everything still applies the same.
Awesome Arcade!!!
@UnsignedArduino’s insanely cool website! Makes finding extensions SO much easier and simpler. 70+ extensions! Also a great page on some useful tools for arcade.
Saint 11 Pixel Art Tutorials
Insanely useful - anytime I’m stuck this is the first place I look for help. It’s got everything from jump animations to tiling to parallax to gems.
Slynyrd Pixel Art Blog
Great pixel art blog to be inspired and learn from. Slynyrd has an amazing style go have a look! Also posts occasional tutorials on stuff like walk cycles and tiling which is also great.
Lospec!
The website for colour palettes (even makecode uses it!)
I have hundreds of saved palettes, this is the perfect website for searching for a fresh palette for a game or a new artwork. Lospec’s gallery also has some great art!
Super Colour Palette
A great tool for making palettes. Super helpful for getting to grips with the basics of colour theory, it creates palettes with perfect hue/sat/bright shifts. I used this a lot when starting out but with enough practise you can do what this website does manually. I find that it’s better to fine tune it manually as colours aren’t all weighted equally and sometimes in a palette you might want a greater focus on some colours, so perfectly equidistant shifts limits that.
Pureref
Great program for collating a moodboard/inspo, referencing when drawing or just having a free window to display stuff in. It’s very simple, but very versatile! Sometimes I use it for non art stuff too lol. Pefect for people like me with only one screen. Only for windows, linux and mac (sorry invalid!)
Font Editor
I love custom fonts! Only works with fancy text though.
Check out my topic on it for some custom ones I’ve made
Image Manipulator
This amazing website made by @YuHayate is so useful for importing art externally! (for me it’s for Aseprite) It’s got a great custom palette feature so your image doesn’t need to switch around colours when copied in the editor. + theres some nice post processing tools like floyd steinberg dithering and blurring as well as the standard scaling/resizing.
Posemaniacs
I haven’t used this one a lot but I can tell that this website is super useful for anything anatomy. Learning anatomy is super scary so websites like this are great to get good refs from!