I was on surfing on the web and stumbled on these two EQ “cheat sheets” that seems to be quite useful!
The first is made/shared by an user called fredv on cheatography.com and it lists pretty good tips for equalization by frequency and by instrument with a glossary.
You can also download this as .PDF from the website. Go check it out.
The second is made by Matthew Sargeant and is aimed to sort out the frequencies in EDM tracks.