Hello CNC instructor looking for some help

After many years of not using CNC machines in back at it.
My new shop has a hass mini mill, 3x kent cnc mills, 5x lathes, Small heat treating furnace, 6x Surface grinders, 3Dprinter.

i'm trying to get some cnc routers and cnc laser.

I need help ordering material and finding new and exciting projects for students.

Any materials besides 6061 t-6 aluminum or what kind of aluminium is most forgiving when machining?
I'm also considering ordering delrin, hdpe, or corian easy to machine and cheap to find?
I'm also looking for a way to get some cutoffs and materials donated for student cnc classes or at a low cost for educational use.

Any help would be appreciated.
Thanks,
Mike