The point here is that Tarmogoyf is an individually powerful card - it's often a 2-mana 4/5 or better - but if the opponent is able to assemble all of Bonescythe Sliver, Megantic Sliver, Syphon Sliver and Galerider Sliver against it at the same time, then Tarmogoyf is just not good enough
That said, some crossovers feel like they come right out of left field
There are some clear, high-value cards you might have heard of Mana Reflection, Dryad of the Ilysian Grove, and Dark Depths
This can help you accumulate the cost needed for Hyper Beam, which does 50 damage and lets you flip a coin to see if you can discard one of your opponents Energy cards.
If youre playing a deck that relies on +1/+1 counter synergies, Inspiring Call is a great way to restock and avoid being punished by a board wipe after emptying your hand