Like most Magic: The Gathering cards, the value of Grond, the Gatebreaker depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (The Lord of the Rings: Tales of Middle-earth)
Get as many artifacts as possible, often in the form of 2/2 Necron Warrior tokens
There are so many cards in it that I just dont want in my collection, but the good cards are really good
Use some other real cards as a reference when you do this test
Another detail to consider is the card's text clarity
For example, exiling a Battle Brawler (a creature with As long as you control a red or white permanent, Battle Brawler gets +1/+0 and has first strike) with Soulflayers delve ability wont cause Soulflayer to have first strike, even if you control a red or white permanent