Finality counters work on any permanent, not only creatures
We also have scry payoffs outside of our commander: Arwen Undomiel and Elrond, Master of Healing pump our team, The Temporal Anchor lets us play the cards we bottom, and Lost Isle Calling can take an extra turn while drawing cards
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And Psychotrope Thallid is just plain better than Soothsayer in a Saproling deck
On the other hand, the other abilities rarely matter to you
But for those looking for condensed advice: the ingredients of truly fierce competitive decks are infinite combo pieces, tutors to find them quickly, resource acceleration (mana rocks) to cast all those cards faster, and cheap interaction to stop opposing combos developing