Once per turn, if a face-up "Crystal Beast" monster(s) you control is destroyed by battle or card effect: You can Special Summon 1 "Crystal Beast" monster from your Deck. You can send this face-up card from the field to the Graveyard, then target 1 "Crystal Beast" card you control and 1 other card on the field; return them to the hand. You cannot activate these effects in the same chain.
Bounces a Crystal Beast along with another card back to the hand.
Special Summon only happens when your Crystal Beasts are destroyed.
Removes itself when using the second effect.
Search this card with Rainbow Bridge.
Crystal Conclave essentially gives a floating effect to all your Crystal Beasts. The best monsters to Special Summon from your deck would be Sapphire Pegasus to search another Crystal Beast, or Ruby Carbuncle to Special Summon the Crystal Beasts in your Spell/Trap Zone. The constant floating also lets you quickly fulfill Rainbow Dragon’s summoning condition
Returning a Crystal Beast monster to your hand is especially good with Sapphire Pegasus because it allows you to reuse his effect. You can target Crystal Beasts in your Spell/Trap Zone for this effect. The other card you remove from the field should be a difficult to summon enemy monster like an Extra Deck monster.
Because Rebound can only be chained to the activation of Trap Cards and not the activation of their effects. (And Horde doesn't return anything to the hand when it first resolves.) Pretty much every Counter Trap works this way, there's only 1 Counter Trap that can be chained to S/T effects (and it won't exist in Duel Links for a long, long time.)