I like working with aluminum. I had some flat stock and decided to try making a pick.
I made the small one first out of thick stock. It's about 2.5mm with nice contour for my fingers.
The larger one is 1.5mm and the size of a Dunlop stubby triangle.
They both have nice tone. Not too different from my plastic picks but with a slight metalic sound as would be expected.
I like them more than I expected to.
Nothing earth shattering, but it's nice to have a custom touch to my gear.

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'10 American Deluxe HSS Sunset Metallic
'10 JA-90 Thinline Telecaster
'15 Music Man JP-15 Blueberry Burst
'07 Les Paul Standard Faded LCPG #82
'14 Carvin ST300
'12 Carvin CS424S
'66 Guild Starfire IV w/Bigsby
'14 Warmouth Partscaster Daphne Blue

I bought an aluminum "ProPick" at the Dallas Guitar Show a couple years ago just as a novelty/souvenir. It's 0.030"/.076mm which is a bit thinner than a Fender medium celluloid, but it's stiffer than an extra heavy celluloid -- no flex at all (I like stiff picks).

I was surprised at how good it sounds. I expected it to be bright and tinny sounding but it's fat and full sounding with just a hint of metallic clang.

I had a stainless steel pick once that was very metallic sounding. And it tore up nickel plated steel wound strings. Aluminum is much easier on the strings -- no worse than a V Pick.

Heavy celluloid is still my "standard" pick, but I like a little strange now and then so I keep a variety of picks around the house.