Crystal Beast decks might not be all that viable in Duel Links due to limited cards and only 3 spell/trap zones, but it can still be a fun and gimmicky. Using the Crystal Beast monster's effects to put themselves on the spell/trap zone, you can use cards like Crystal Raigeki or Parallel Twister to destroy your opponent's cards. While the skill Crystal Power boosts your monster's attack.
Send 1 to 3 cards from your hand to the Graveyard. Choose the same number of "Crystal beast" monster(s) from your Deck as the number of cards you sent from your hand to Graveyard, and place it/them tin your Spell/Trap Zone as. This Skill can only be used once per turn, and twice per Duel.
Crystal Beast Sapphire Pegasus
|WIND Beast ★4|
ATK 1800 / DEF 1200
|Jesse Anderson [UR]|
Jesse Anderson Lvl 11 & 35 [UR]
|When this card is Summoned: You can place 1 "Crystal Beast" monster from your hand, Deck, or Graveyard face-up in your Spell & Trap Card Zone as a Continuous Spell Card. If this face-up card is destroyed while it is in a Monster Card Zone, you can place it face-up in your Spell & Trap Card Zone as a Continuous Spell Card, instead of sending it to the Graveyard.|
Crystal Bond is a great search card, it allows you to search 2 Crystal Beast monsters from your deck placing one in your hand and one in your spell/trap zone. You can search Sapphire Pegasus to your hand and then Normal summon it to add another Crystal Beast into your Spell/trap zone, giving you a total of 3 searches.
Crystal Raigeki exchange a Crystal Beast in your backrow to destroy a card your opponent controls. The advantage of Crystal Raigeki is that you can use it during your opponent's turn to disrupt his plays, but as a trap it is also at a disadvantage because it needs to be set a turn before activation.
|LIGHT Dragon ★10|
ATK 4000 / DEF 0
|Jesse Anderson [UR]|
Jesse Anderson Starter Deck [UR]
|Cannot be Normal Summoned or Set. Must be Special Summoned (from your hand) by having 7 "Crystal Beast" cards with different names on your field or in your Graveyard, and cannot be Special Summoned by other ways. This card cannot activate its effects the turn it is Special Summoned.|
● During either player's turn: You can send all "Crystal Beast" monsters you control to the Graveyard; this card gains 1000 ATK for each card sent.
● You can banish all "Crystal Beast" monsters in your Graveyard; shuffle all cards on the field into the Deck.
You can make a Crystal Beast deck made to summon Rainbow Dragon. While it's really not all that viable in the game due to the limitations in Duel Links, you can still get a somewhat reliable deck that can also work as a regular deck, but can be inconsistent because of the need for Last Gamble.