To start with, I must say that your lineart is really nice! Most of your anatomy is on point and the variety you draw in is great. :)
As for the colouring there are places where I can admire the colour scheme and others where I’m slightly confused. To begin, there are three main colour schemes: Mono-chromatic, Analogous and Complementary. Each of which convey their own mood, you can search this up on the internet.
The shading is also something, some are shaded with only black. In my opinion, I don’t find this visually appealing as it looks kind of dull? Usually shading depends on he lightsource, for example in a colder piece you may use more blue and purple shades. Shifting hues is another tip for shading, usually using de-saturated colours appear more aestheticlly pleasing, may give more depth and dynamic to the artwork.
Once again, congratulations on all those drawings! Remember, don’t be hesitant to ask for assistance. Keep drawing! :D
I’m always happy to give out some constructive criticism!