Pros : PSA is seen as the experts when it comes to older cards, especially for anything pre-1970s
Any card with a tap symbol on it will be from Revised not Unlimited
(10/1/2009) The effect from the ability overwrites other effects that set power and/or toughness if and only if those effects existed before the ability resolved
For example, here are some of the earliest: Auriok Steelshaper was a generic 1/1 for 2 mana on its own, and if it was equipped, only Soldiers and Knights would get a bonus, and it was just +1/+1
The Pokemons black coloring makes it instantly recognizable, so its no wonder you can find it selling for nearly $5000 for graded copies
Katara, Waterbending Master - $18 to $35 There's some big price spikes in the eternal-legal set, which is pretty common for Jumpstart, as the desirable cards end up being pretty scarce