The solution is simple. Buy games you really want, but put them in your inventory until Trails comes out. Put any keys you get in a bundle in a word document or spreadsheet.
But the question is, can you wait? Or will you give in to your greed and buy so many games that Trails becomes your 1500th game, or your 2000th game?
I was contemplating this idea, but I'm so forgetful... Last time, when I checked keys from older bundles for my giveaway, I found something like 5 or 6 steam games I haven't redeemed, it probably was later additions to bundles, that I forgot to check. But if I would make spreadsheet and pin a link to it somewhere visible... that might work.
This question is even more serious, what if I wanted to buy something on steam?! Let's say Transformers games went on some insane sale, what then?! oh horror
Always Remember Me keys are up on Indie Gala. Deluxe edition and everything
That makes 998th game for me, time to make very hard decision.