They can't be the target of spells or abilities, their static abilities have no effect on the game, their triggered abilities can't trigger, they can't attack or block, and so on
Of course, my terms would be having Pauper (a specific constructed format where only Common cards are allowed in ones deck) and Singleton (a constructed deck format where ones deck may not contain more than one of any individual card) always available formats, but they do show up as special events
Teshar can also help you rebound after a board wipe, especially if you have many cheap historic spells to cast
This is the highest-charting Simic card
What do white border MTG cards mean
That means they often have the lowest price, plus there is a ton of inventory on the site as well