Senbura currently runs 3 basic versions of gacha. In the future, event gacha may be announced for event cards.
Paid Gem (3* upwards) - daily 5 Gem Roll (labelled with a yellow bubble)
BattleGem Gacha (3* upwards) - each roll requires 15 gems, a 10-roll requires 135 gems which will guarantee you at least one 4* Super Rare card.
Point Gacha (2* and 1*) - each roll requires 50 Gacha Point, a 10-roll requires 500 Gacha Points. You also have a chance to obtain 3* Rare cards here.