The effects of two of the cards used by Jim Crocodile Cook and one by Chazz Princeton have been revealed.

Dark Alligator
Dark Reptile / Effect
LV8 2500/2300
You can Tribute Summon this card by Tributing 1 Reptile monster.
(1) When this card is Tribute Summoned: You can Special Summon “Alligator Tokens” (Reptile/DARK/Level 1/ATK 2000/DEF 0) up to the number of Reptile monsters Tributed for this card’s Summon.
(2) If this Tribute Summoned card is destroyed by battle, or by an opponent’s card effect while in its owner’s Monster Zone: You can add 1 Reptile monster from your Deck to your hand, except “Dark Alligator”.

Rinneryuu Samsara / Samsara Dragon
LIGHT/Dragon
Level 1
0/0
You can only use this card name’s (2) effect once per turn.
(1) This card can be treated as 2 Tributes for the Tribute Summon of a Dragon monster.
(2) You can banish this card from your GY, then target 1 Level (5?) or higher Dragon monster in your GY; add it to your hand, then, immediately after this effect resolves, you can Tribute Summon it.