Riku help

[Agrajagzz9]

So i was wondering what people thought were good copy targets for riku's second ability. Obviously things like {zealous conscripts} {thragtusk} {phyrexian metamorph} are obvious choices  but what else would work? Thoughts? 

{riku of two reflections}

[Guypocolypse]

Wizzard Aggro!!!!!!!!!

[Moneekahh]

Rampaging baloths
Pelakka wurm
Great whale
Spitebellows
Mindwrack liege
Acidic slime

[BlackJester]

{Rampaging baloths}
{Pelakka Wurm}
{Great whale}
{Spitebellows}
{Mindwrack liege}
{Acidic slime}

[Gorzo]

Honestly Riku is so versatile that anything with an ETB effect or a combat-related keyword or trick makes for crazy copy material. Creatures that produce mana are strong choices as well, to help keep more copies coming. As for copying non-creatures, extra turn spells like {time stretch} are always good choices.

[Thorn]

{Terestadon}
{Bogardan Hellkite}
{Thunder Dragon} (if you can protect riku)

[BlackJester]

Look up the DotP2013 decklist for Yeva "Ancient Wilds".  Some good green ETBs.