There’s no way to tell for sure. You might as well go with something you like.
Because if it doesn’t turn out the way you want it, you’ll always have something nice to look at and appreciate.
@mervjackson is talking about boxes 1-2x the retail price. I’m currently selling Steam Siege for roughly 0.5x.
If I had to pick one right now, I’d personally pick Plasma Blast. I’m a bit biased for nostalgia reasons but the price point imo is still really great compared to the other sets around it.
Though I’m not sure how much @mervjackson wants to budge from the ‘1-2x the retail price’-pricepoint; Ultra Prism is already above 2x retail price. But Burning Shadows on the other hand, is still readily available just above 1x retail price.