I have a few MTG cards that have been stamped in a Competitive REL draft tournament.

What would be the best way to indicate that they are stamped in my collection? I don't want someone to be surprised when they trade / buy a card and end up with a stamped one.

I'd love to see a flag for this (e.g., "event stamp"), as I'm one who would not want to receive stamped cards without agreeing to it first.

There should be other flags for "signed", "altered", etc. Personally, I'd like to see a notes flag and field.

There's already a flag for Signed, but having ones for Event Stamp, and Altered would be great. The notes field would be very useful too.