practice

• http://www.eggazyoutatsu.net/atarichanDrawer.html
• http://reference.sketchdaily.net/en/
• https://line-of-action.com/

colors

• http://paletton.com/
• http://www.degraeve.com/color-palette/

misc

• http://tholman.com/texter/

references

• https://www.maikubokeh.com/