Which colour / colour plastic is best to find when drops to floor before the carpet monster reaches that important part.

White

Gray

Green

Dark Yellow

Black

I found white easy

It depends on the carpet color, which is something to think about next time you go to replace it. I'm sure it is common practice to match sprue and carpet samples for best contrast. Laminate and tile floors, and even concrete don't help much as the more neutral colors seem to hide small bits very well, and they increase the bounce range, even on tiny bits. I think glow in the dark plastic might be best as you could then find parts by turning out the lights.

As Russ has already pointed out it depends on the colour of your carpet, if you have white carpet then white plastic would be the worst colour. A hard floor just increases the bounce factor.

The worst carpet is a multi colour patern deep pile.

I think Luciano hit it right on the head, "multi color deep pile" or shag as we call it in the states. My carpet happens to be almost a perfect match of Dragon grey.
I get around it by using a painter's drop cloth. It also catches all those little pour plugs that Dragon likes to use. In my case green would be the best.
Stay warm !
Tom

I use a sheet of stiff, white plastic, under my desk and chair. I have lost only one part in a year and a half. The hardest part is sweeping up sprue bits.

Or, use glow-in-the-dark carpet! Then the parts would show up as dark spots...

A Model Railroader friend wears a long apron. (covers his chest and lap). The bottom of the apron has islets that attach to hooks on his modeling table/desk. Flying parts almost never reach the floor

I can just see it now ... flying table and everything on top of it when I go to get up! ... and me stretched-out on the floor from getting clothes-lined!!!

I have just begun to use an anti-concrete (I work in a garage) monster aid. I had a cheap rain cape lying around, it serves a double purpose,
1: It stops the descent of parts and other items to the floor
2: It keeps my wife happy as my clothes are covered and so I will not get paint on my clothes (I won't tell her there are no sleeves )
I secure the cape to my worktop by clamps and as it is a cape you can't forget your wearing it.

Here are a couple of piccies of said fixing

Aprons, capes, hooks, clamps, straps, tie-downs ... nope, not buying into it! ... Hmmmm ... How about getting the wife to sew-on some Velcro strips? — instant quick-release!

Ultimately, I think the only way to defeat the Carpet Monster is to move operations into a 'clean room' at the CDC!