A massive archive of user-uploaded vectors. Quality varies, but the top-rated items are professional grade.
While not "industrial" by design, these platforms are increasingly used for modern flat-UI HMI design. free hmi graphics library
If you have ever scrolled through the stock symbols in a basic HMI software package, you know the frustration. The pumps look like clip art from 1998. The tanks are static. The buttons have no tactile feedback. A massive archive of user-uploaded vectors