Old cutting board, hockey puck,, whatever, just be aware the IF your safety switches are all still working and you hit a bump and the stand is deflected down before the spring hauls it back up, its gonna cut out & BakkFarr like nobodys bizniss,,
Otheres have done this for Oil Checkin reasons,, No one has demonstrated any pain or loss or suffering from doing that and adding oil till its visible at the veeeerry bottom of the window, Of course, the window would indicate over full when the bike is standing up.. I never did it, a few did, no one ever wrecked a motor..

If you wanted to be super fancy, you could get some of that spray-on rubber coating.  Several thick coats of that, and you won't have to carry around anything.  If you want to be basic, go with the flattened beer can or an empty dip can.

Was it Serow that bolted a cut up hockey puck to his kickstand?  It kinda looked like a horseshoe.  

I put some heavy heat shrink tubing on the end of mine....it held up for a little while.

I now just have a small piece of carpet in the place where I park my bike inside (painted garage floor). Outside I don't worry about it as I have not noticed any marks on the concrete.....a small rubber floor mat would work where you park the bike.

I wonder if I took the kickstand to those folks that spray bedliner on pickup trucks (Rhino, Line-X, etc).........and had them spray the bottom of the foot on the kickstand.  I have tried sticking rubber products onto metal before with glue or two sided tape, and it doesn't work well as the rubber flexes and the metal doesn't and it breaks the bond.  You might also be able to just smear some epoxy on the foot and let it harden.....or epoxy a hard plastic sheet that doesn't flex like rubber.  As a last resort, you could drill a hole in the foot and bolt on a rubber foot (or hockey puck).  Serowbot did this as the longer shocks he used makes the kick stand too short and the bike leans over a long way.

Go to a few motorcycle events.... some vendors give away the "plastic pucks" that you throw down for your stand.

Most MC stores and dealers sell them, sometimes the vendors give the stores a few freebees. Ask your dealer, maybe they will give you one with their business name on it.