Vastmana Relic

Vastmana Relic costs {1} less to cast for each
artifact you control with a mana ability.
Whenever Vastmana Relic attacks, you may pay {x}{u}. If you do, search your library for an
artifact card with mana value X and a mana
ability, reveal it, and put it into your hand, then shuffle.
The ancient magic that fuels its steel heart burns with
an eerie longing.