Anvil of Bogardan

Players have no maximum hand size.
At the beginning of each player's draw step, that player draws an additional card, then discards a card.

Fauna Shaman

{G}, {T}, Discard a creature card: Search your library for a creature card, reveal it, put it into your hand, then shuffle.

Diplomatic Escort

{U}, {T}, Discard a card: Counter target spell or ability that targets a creature.

Harvest Mage

{G}, {T}, Discard a card: Until end of turn, if you tap a land for mana, it produces one mana of a color of your choice instead of any other type and amount.

Salvage Drone

Devoid (This card has no color.)
Ingest (Whenever this creature deals combat damage to a player, that player exiles the top card of their library.)
When Salvage Drone dies, you may draw a card. If you do, discard a card.

Preordain

Scry 2, then draw a card. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Library of Leng

You have no maximum hand size.
If an effect causes you to discard a card, discard it, but you may put it on top of your library instead of into your graveyard.

Grolnok, the Omnivore

Whenever a Frog you control attacks, mill three cards.
Whenever a permanent card is put into your graveyard from your library, exile it with a croak counter on it.
You may play lands and cast spells from among cards you own in exile with croak counters on them.

Trickster Mage

{U}, {T}, Discard a card: You may tap or untap target artifact, creature, or land.

Careful Study

Waterfront Bouncer

{U}, {T}, Discard a card: Return target creature to its owner's hand.

Greenseeker

{G}, {T}, Discard a card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Thought Courier

Breakthrough

Draw four cards, then choose X cards in your hand and discard the rest.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Dreamscape Artist

{2}{U}, {T}, Discard a card, Sacrifice a land: Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Merfolk Looter

Occult Epiphany

Draw X cards, then discard X cards. Create a 1/1 white Spirit creature token with flying for each card type among cards discarded this way.

Turbulent Dreams

As an additional cost to cast this spell, discard X cards.
Return X target nonland permanents to their owners' hands.

Nostalgic Dreams

As an additional cost to cast this spell, discard X cards.
Return X target cards from your graveyard to your hand. Exile Nostalgic Dreams.

Dawnstrider

{G}, {T}, Discard a card: Prevent all combat damage that would be dealt this turn.

Magus of the Bazaar

{T}: Draw two cards, then discard three cards.

Noxious Revival

({G/P} can be paid with either {G} or 2 life.)
Put target card from a graveyard on top of its owner's library.