In the event that you are pressed for life, even in a Commander game, Sylvan Library still lets you draw two cards and put two back, at the very least improving the quality of cards in your hand for a turn or two
That goes double for a Niv-Mizzet, VisionaryNiv-Mizzet, Visionary deck, where the more efficient burn spell you could be playing instead for one mana will draw you more cards to get more burn spells and keep the whole cycle going
Things are even worse if you do this with commons
Nature's Lore is also great because the land you find doesnt enter tapped, so it basically only costs one mana unless youre fetching a tap land
Maui - Half-Shark is a 6 ink cost inkable card with a skull-cracking strength of 7 and a robust 5 willpower
These, in exchange, have certain thresholds that, when met, grant a certain benefit or ability