Question regarding slower projectiles change

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MuTayShuN wrote:

"Slower Projectiles
The Slower Projectiles Support Gem now grants a lower value of Less Projectile Speed than before; This is because this single support was massively multiplying the close range damage of certain skills, and all of them were being balanced around the value from this support. It also means we can be more generous with projectile speed granted by other sources.

Molten Strike, Magma Orb and Ball Lightning have had their damage and some other properties improved, as their close range damage is now affected by lowered projectile speed."

I guess my question is, other than ball lightning and other listed skills, what else was using slower projectiles to boost damage? Sorry for the noob question.