The spells you're going to want the most are what are called "removal spells"these are the spells that permanently neutralize your opponent's creatures by either dealing damage, keeping them tapped, or just straight-up destroying them
Searching up cards like Daybreak Coronet, Spirit Mantle, and Ethereal Armor will make Zur more and more powerful, and he will quickly become a virtually untouchable enchanted monster capable of one-shotting other players with commander damage
Its a card that anyone whos not got it in play hates, because what actually happens is that everyone will pay the cost for a turn or two, but once someone stops, everyone does
Green is the best individual color in the color pie at performing this task, as it provides ample ways to put extra lands onto the battlefield from your hand or deck as well as efficient ways to add extra mana to your mana pool via creatures, enchantments, and artifacts
Thoughtseize is the most powerful of the family, casting a shadow over all other options
Additionally, every rare or mythic rare borderless card in Foundations has a mana foil version