Answer:
There are slightly over 30 species of dolphins in the world. Including fresh water dolphins and salt water dolphins.
Such as:
Atlantic Hump-Backed Dolphin
Atlantic Spotted Dolphin
Atlantic White Sided Dolphin
Black Dolphin
Bottlenose Dolphin
Clymene Dolphin
Commersome's Dolphin
Dusky Dolphin
False Killer Whale
Frasier's Dolphin
Heaviside's Dolphin
Hector's Dolphin
Hourglass Dolphin
Indo-Pacific Hump-back
Irrawaddy Dolphin
Long-finned Pilot Whale
Long-Beaked Common Dolphin
Long-Snouted Spotted Dolphin
Melon Headed Dolphin
Northern Right-Whale Dolphin
Orcas (Killer Whale)
Pantropical Dolphin
Pacific-White Sided Dolphin
Peale's Dolphin
Pygmy Killer Whale
Risso's Dolphin
Rough Toothed Dolphin
Short Finned Pilot Whale
Short Beaked Common Dolphin
Southern Right Whale Dolphin
Striped Dolphin
White Beaked Dolphin