Random card ideas:

Chess Pawn
Artifact Creature - Peasant (C)
A deck can have up to eight cards named Chess Pawn.
When Chess Pawn deals combat damage to an opponent, sacrifice it. If you do, search your library for a chess piece, reveal it, and put it in your hand. Then shuffle. (Nobles, Knights, Clerics, Peasants and Vehicles are chess pieces.)
2/1

Twister Spinner
Artifact (U)
, Tap an untapped creature you control: Add one mana matching any of that creature's colors.

Pass Go
Sorcery (C)
Put two +1/+1 counters on target creature. You gain 2 life.

Catan
Enchantment - Game (U)
At the beginning of your upkeep, roll a six-sided die. On a 1, every player discards a card. Otherwise, each player creates a treasure token for each permanent they control with a mana value equal to that roll.

Triple Word Score
Instant (U)
Replace the number 1 in the text of target instant or sorcery spell with the number 3. (This replaces numerals, but not number words or symbols.)

Bluff
Sorcery (U)
Manifest the top card of your library. It gains haste until end of turn. At the beginning of the next end step, if that card is face-down, return it to its owner's hand.

Jenga
Enchantment - Game (R)
At the beginning of your upkeep, search your library for a card, exile it, then shuffle your library. Any opponent may exile X cards from the top of their library, where X is that card's mana value. If no player does, put that card on top of your library.