Cheapest priced copy (March of the Machine): $7.49 at Card Kingdom, near mint, their price list as of .
Hoarding Broodlord 
Creature — Dragon · 7/6 · Rare · March of the Machine · #360
Convoke
Flying
When this creature enters, search your library for a card, exile it face down, then shuffle. For as long as that card remains exiled, you may play it.
Spells you cast from exile have convoke.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $7.49 to $11.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| March of the Machine | 110 | Rare | $7.49 | $7.99 |
| March of the Machine | 360 | Rare | $8.49 | $11.99 |
| March of the Machine Promos | 110p | Rare | $7.49Out of stock | $8.99 |
| March of the Machine Promos | 110s | Rare | — | $11.99 |
8 rulings from Wizards of the Coast
- 14 April 2023If another player gains control of Hoarding Broodlord, it's still you who can look at and play the exiled card. That player won't be able to look at or play the exiled card.
- 14 April 2023As long as that card remains exiled, you may look at it. This remains true after Hoarding Broodlord leaves the battlefield.
- 12 January 2024Because convoke isn't an alternative cost, it can be used in conjunction with alternative costs.
- 12 January 2024If a creature you control has a mana ability with {T} in the cost, activating that ability while casting a spell with convoke will result in the creature being tapped before you pay the spell's costs. You won't be able to tap it again for convoke. Similarly, if you sacrifice a creature to activate a mana ability while casting a spell with convoke, that creature won't be on the battlefield when you pay the spell's costs, so you won't be able to tap it for convoke.
- 12 January 2024When calculating a spell's total cost, include any alternative costs, additional costs, or anything else that increases or reduces the cost to cast the spell. Convoke applies after the total cost is calculated. Convoke doesn't change a spell's mana cost or mana value.
- 12 January 2024Tapping an untapped creature that's attacking or blocking to convoke a spell won't cause that creature to stop attacking or blocking.
- 12 January 2024Tapping a multicolored creature using convoke will pay for {1} or one mana of your choice of any of that creature's colors.
- 12 January 2024You can tap any untapped creature you control to convoke a spell, even one you haven't controlled continuously since the beginning of your most recent turn.