mtg.wtf

Whenever you crank Jamming Device, creatures target player controls get -1/-1 until end of turn.

{2}, {T}, Discard the last card you drew this turn: Draw a card.

{3}, {T}: Untap target creature.

Whenever Jangling Automaton attacks, untap all creatures defending player controls.

Whenever a creature you control dies, put two eyeball counters on Jar of Eyeballs.
{3}, {T}, Remove all eyeball counters from Jar of Eyeballs: Look at the top X cards of your library, where X is the number of eyeball counters removed this way. Put one of them into your hand and the rest on the bottom of your library in any order.

(Jasconian Isle isn't a spell, it's affected by summoning sickness, it's blue, and it has "{T}: Add {U}.")
Jasconian Isle enters tapped.
Jasconian Isle doesn't untap during your untap step.
At the beginning of your upkeep, you may pay {U}{U}. If you do, untap Jasconian Isle.

{2}: Target red creature gains haste until end of turn.

{X}: Jaya Ballard Avatar deals an amount of damage chosen at random from 0 to X to any target. Activate only once each turn.

{4}, {T}: Draw a card.

{T}: Add {U}, {R}, or {W}.
{U}{R}{W}, {T}, Sacrifice Jeskai Banner: Draw a card.

{2}, {T}, Sacrifice Jester's Cap: Search target player's library for three cards and exile them. Then that player shuffles.

Jester's Mask enters tapped.
{1}, {T}, Sacrifice Jester's Mask: Target opponent puts the cards from their hand on top of their library. Search that player's library for that many cards. That player puts those cards into their hand, then shuffles.

When Jester's Scepter enters, exile the top five cards of target player's library face down. You may look at those cards for as long as they remain exiled.
{2}, {T}, Put a card exiled with Jester's Scepter into its owner's graveyard: Counter target spell if it has the same name as that card.

{2}, {T}, Sacrifice Jester's Sombrero: Look at target player's sideboard, choose three cards from it, and remove those cards from the match.

Black spells you cast cost {1} less to cast.

Jetmir's Garden enters tapped.
Cycling {3}

{TK}{TK} — Trample
{TK}{TK}{TK} — {3}: Monstrosity 3.
{TK}{TK}{TK} — 2/7
{TK}{TK}{TK}{TK} — 6/5

{1}, {T}: Put a charge counter on Jeweled Amulet. Note the type of mana spent to pay this activation cost. Activate only if there are no charge counters on Jeweled Amulet.
{T}, Remove a charge counter from Jeweled Amulet: Add one mana of Jeweled Amulet's last noted type.

Remove Jeweled Bird from your deck before playing if you're not playing for ante.
{T}: Ante Jeweled Bird. If you do, put all other cards you own from the ante into your graveyard, then draw a card.

{T}, Sacrifice Jeweled Lotus: Add three mana of any one color. Spend this mana only to cast your commander.

As Jeweled Torque enters, choose a color.
Whenever a player casts a spell of the chosen color, you may pay {2}. If you do, you gain 2 life.

{3}, Discard a card: Copy three instant cards chosen at random. You may cast one of the copies without paying its mana cost.
{3}, Discard a card: Copy three sorcery cards chosen at random. You may cast one of the copies without paying its mana cost. Activate only as a sorcery.

Flying
Historic spells you cast cost {1} less to cast.

{T}: Choose target permanent you control or suspended card you own. If that permanent or card has a time counter on it, you may remove a time counter from it or put another time counter on it.

{2}: Regenerate target artifact creature.