[QUESTION] About Icons / Services and Apps

Hello everyone,

I want to know more about services and applications that provide icons for free use.
Since many exploits now use almost the same icon pack / set which are or almost identical, I want to learn more about them.
Are the developers using a specific website or program to access these icons, or are they just designed on Geometry.

And also what websites or applications do you use
(I am currently using Icons8 Pichon)

I will be greatfull for ur answers :)