I would like to suggest the addition of a new filter for searching

"Cards involved in Trades" which would be able to be set to True or False

This would be especially handy to filter out cards involved in trades, and is likely very easy since we already see in the list of cards a green arrow for those involved in trades (so the data is there).

In my case, I could then easily filter out cards involved in trades when composing a list of cards I know I can sell elsewhere, avoiding the accidental sale of cards that are going to be traded away, but have not been removed from my tradelist because the trade has not been completed as yet.