It is card 2 of the 132 in the official Gym Heroes checklist. If you are completing the set, mark it in your collection to keep track.
Rarity: Holo Rare. The symbol in the bottom corner confirms it at a glance, as explained in Pokémon card rarities explained.
It exists in several finishes (Holo, 1st edition). Each one has its own price; the average above is for the regular version.
Artwork by Ken Sugimori. Some collectors chase every card by the same artist: how to start (in Spanish).
Abilities
Bench Guard Pokemon Power
As long as Brock's Rhydon is Benched, whenever 1 of your Benched Pokémon is damaged, you may do 10 of that damage to Brock's Rhydon instead. (If more than 1 of your Benched Pokémon is damaged at the same time, you may use this power once for each of them.)