First and foremost, great work by all the team so far on this, though not yet released, all the mentioned filters within the latest (discord) announcement are extensive and detailed, to the point that it's hard to think of other specific single filter, really can't wait for the client update to fully enjoy all those great features.
Back to the suggestion part, it's about "customized tags", or the "pokemon tags", which were already mentioned in the announcement lately as a possibility. But instead of typing the specific command(s) for it, I'd suggest a "scrollable customized tag list" as below. (player feel free to create their own tag)
Note: not a push, just brainstorming idea