I have learnt a lot of useful websites, apps and such that are very useful to art on roblox.
dafont.com - fonts of all kinds like horror, cartooney and greek.
flaticon.com - Find millions of user generated icons (requires attribution unless you have a premium liscence.
starburstgenerator.com - Make starburst png’s or SVGs.
getpaint.net Paint dot net is a very straightforward and user friendly art software, and 100% free.
iconsdb.com Free icons, that you can customize to your liking! Thanks to @ReturnedTrue for the recommendation!
http://google.github.io/material-design-icons/ Thanks to @Streeteenk for the recommendation!
https://github.com/Corecii/Transparent-Pixel-Fix/blob/master/README.md Thanks to Streeteenk for the recommendation!
https://material.io/resources/icons/?style=baseline Thanks to Streeteenk for the recommendation!
https://www.gimp.org/ And https://inkscape.org/ Thanks to @PrincessPandaBlox for the recommendation!
www.photopea.com - Pretty much photo shop
I hear at least , but free.
If you have any suggestions please say so down below!