The most valuable run of Pokmon TCG Base Set cards is the 1st Edition
To double a creature's power, that creature gets +X/+0, where X is that creature's power as Double Trouble resolves
Choose from COUNT CHOCULA, FRANKEN BERRY, BOO BERRY, FRUTE BRUTE, FRUITY YUMMY MUMMY, and the latest Monster
These tokens play really well with blue because they let you get creatures without needing to play creature cards, but also good with black because you can sacrifice the creatures in various ways, and white because there are various payoffs for having a lot of creatures and/or humans specifically
card to Nami - A Fist of Divine Speed, she unlocks a once-per-turn counter ability that allows the player to trash a card from their hand to grant her an immediate plus 2000 power buff for the remainder of the turn