Filter artifact
Filter artifacts, like filter lands, allow players to exchange incorrectly colored or colorless mana into a color of their choosing.
Description
Common artifact mana was often weak as fixing for many years before Ravnica: City of Guilds, which produced some of the strongest fixing in the Signet cycle, 2-mana artifacts which filtered 
into a color pair. However, this meant that nongreen decks had a consistent colored ramp, which undercut green's ramping spells, as Rampant Growth was already quite strong. Five-color mana stones eventually got their average rate at three mana, giving space for weaker fixing at two and one, which is where filter artifacts reside.
These artifacts are often common in rarity and low in power and mana cost, as they are not meant to be premium mana fixing; this can be achieved by either costing two mana to filter into one colored, requiring a tap or can only fix once through sacrificing. Unlike mana stones, these artifacts rarely generate mana on their own. However, they can provide other utility, such as being creatures or drawing a card.
Some are termed as "eggs", where sacrificing (or "cracking") them gives both mana and a card. As this can let them be cycled through easily, at mass they can become the cornerstone of certain combos, such as in Second Sunrise or Krark-Clan Ironworks combo.
List of filtering artifacts
If not specified otherwise, the cards filter into 1 mana of any color.
Mana only
- Celestial Prism —
& filter 
. - Gemstone Array — Filter & 1 Charge counter.
- Mana Cylix — & filter .
- Mana Prism — & filter ; can also tap for
. - Prismatic Lens — & filter ; can also tap for .
- Pyramid of the Pantheon — & filter ; taps for 3 mana once powered up
- Standing Stones — Filter & 1 life
- Signets — & filter into:
Creatures
- Coal Golem (3/3) — Filter
into 
and sacrificing - Codie, Vociferous Codex (1/4) — & filter
into 
- Crossroads Candleguide (3/4) — Filter ; exiles a card in graveyard
- Gravestone Strider (1/3) — Filter once a turn; can exile one card in a graveyard
- Pili-Pala (1/1) —
& filter - Prismite (2/1) — Filter
- Salvaged Manaworker (1/3) — Filter once a turn
- Scarecrow Guide (2/1) — Filter once a turn
- Shire Scarecrow (0/3) — Filter once a turn
- Signpost Scarecrow (2/4) — Filter
- Stonework Packbeast (2/1) — Filter
- Attendants (3/3) — Sacrifice & filter into:
Draws a card
- Arcum's Astrolabe (Snow) — & filter ; draws as an entry ability.
- Energy Refractor — Filter ; draws as an entry ability.
- Prophetic Prism — & filter ; draws as an entry ability.
Requires sacrifice (eggs)
- Astrolabe — Filter into 2 mana of any color; draws on the next upkeep
- Barbed Sextant — Filter ; draws on the next upkeep
- Chromatic Sphere — Filter ; draws as a mana ability
- Implements of Sacrifice Filter for 2 mana of any color
- Chromatic Star — Filter ; draws as a "dies" ability
- Golden Egg (Food) — Filter ; draws as an entry ability
- Guild Globe — Filter into 2 different mana; draws as an entry ability
- Jack-o'-Lantern — Exile from your graveyard & filter ; draws as a "dies" ability
- Kaleidostone — Filter
into ; draws as an entry ability - Terrarion — Filter into 2 mana of any color; draws as a "dies" ability
- Wizard's Rockets — Filter
into X mana of any color; draws as a "dies" ability - Eggs — , draws a card & filter into:
Other
- Barrels of Blasting Jelly — Filter once a turn; Can be sacrificed for to deal 5 damage
- Mox Lotus (Acorn) — Filter
; taps for 
. - Mystic Skull — & filter ; transforms to a 5/6 for
- North Star — & mana washing for .
- Urn of Godfire — Filter ; destroy a creature or enchantment for
and sacrifice.