As far as I know, MySQL supports string matching via regular rexpressions natively since v5.7, so this shouldn't be too difficult to implement, but it would provide a lot of value for the more technically savvy users. I do a lot of searches via Scryfall that supports regular expressions in a wide array of fields, and not having this option on Deckbox makes me overlook a lot of cards in my collection by accident.

When I trade parts of my collection (I only trade locally), I usually create a pseudo-deck where I put all the cards I am trading away. After I actually make the trade, I update each card's count by subtracting the amount I have added to this 'deck'. In most cases this will be just a few copies, so it isn't some high-level math.

Hope this little trick helps you.

Honestly, I think the owner should think of shrinking the scale and focussing on something specific. I was mainly using Deckbox for its excellent collection management features, and I still can't find a better alternative. Its current main benefit over its competitors is that you can store your entire collection and technically infinite amount of decks for free, while also having the option to cross-reference the missing cards with your collection. I also really like the deck builder, because I can assign custom tags to cards in my decks, which is really helpful when I am assessing what am I missing in my deck.

However, card search could really be better. It feels like hasn't evolved at all since 2017, and I just find it really annoying that there is still no way to filter cards by commander identity. Meanwhile, powerful search engines like Scryfall exist, which not only have a much better search capabilities, but also is updated more frequently, uses multiple card price sources, has handy links to other useful websites like EDHREC and MTGTop8 etc, and its interface also looks much more polished. I really wish I could just use a combination of Scryfall's search and Deckbox's deckbuilding/collection managing capabilities.

Perhaps, instead of having to focus on supporting its own card database and Oracle text (which is quite often outdated), Deckbox could just use MTGJSON. This would allow the owner to completely get rid of the hassle of having to manage own card database updates and shift the focus towards Deckbox's strong sides -- a combination of a great deck builder and excellent collection manager.