mtg cards with shadow Death's - Mystery Booster 2: Convention Edition #180 (English) players cant cast spells or activate abilities that arent mana abilities.) Shadow the Hedgehog on Radical

Any mana rocks you have, like Sol Ring and Basalt Monolith, are reset every turn, giving you plenty of extra mana to play with during your opponent's turn to cast spells or activate the abilities of your other artifacts

The Ruinous Powers

In terms of a serious threat in blue that costs five mana Meluko trumps all the alternatives however when facing the likes of Banelsayer Angel, Wolfir Silverheart, Seige-Gang and Thundermaw Hellkite from other colours you are much better off casting a Time Warp and making a six drop

However, the Desert typing is crucial for some decks, and there exist Commander decks that don't mind a critical mass of cyclers, even if some are worse than others

Even still, seems unlikely