Umbral Mantle

Equipped creature has "{3}, {Q}: This creature gets +2/+2 until end of turn." ({Q} is the untap symbol.)
Equip {0}

War's Toll

Whenever an opponent taps a land for mana, tap all lands that player controls.
If a creature an opponent controls attacks, all creatures that opponent controls attack if able.

Yurlok of Scorch Thrash

Vigilance
A player losing unspent mana causes that player to lose that much life.
{1}, {T}: Each player adds {B}{R}{G}.

Spectral Searchlight

{T}: Choose a player. That player adds one mana of any color they choose.

Mana Reflection

If you tap a permanent for mana, it produces twice as much of that mana instead.

Mana Flare

Whenever a player taps a land for mana, that player adds one mana of any type that land produced.