Frontier Bivouac

This land enters tapped.
{T}: Add {G}, {U}, or {R}.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Riku of Many Paths

Whenever you cast a modal spell, choose up to X, where X is the number of times you chose a mode for that spell —
• Exile the top card of your library. Until the end of your next turn, you may play it.
• Put a +1/+1 counter on Riku. It gains trample until end of turn.
• Create a 1/1 blue Bird creature token with flying.