Dungeon Master's Guide 5th Edition, Forgotten Realms Wiki
Wondrous Item Uncommon
A figurine of wondrous power is a small statuette ranging in size from a grown man's hand to the size of a little finger, that is similar in shape to the extra-planar creature that it turns into. These rare items transform into many types of bestial planar creatures that understand common and follow the orders of the wielder of the statuette. These creatures are called by the name given to the creature upon the item's creation. They cannot reside on the prime material plane for large amounts of time and therefore are bound by the figurines to return to their home planes to rest after a set amount of time on the prime. If the creature is slain while on this plane it will revert back to statuette form and live on, but if the statuette is destroyed the item becomes worthless and loses all enchantment. Depending on the strength of the enchantment this artifact's effects should be permanent unless passed through an anti-magic field, which could disrupt the base structure of any magic item.
Blue quartz eagle
Transforms into an Eagle for 24 hours per ten days.
Bronze griffon
Transforms into a Griffon twice per week for 6 hours per use.
Coral dolphin
Transforms into an especially intelligent Dolphin twice per ten days for 4 hours per use.
Ebony fly
Transforms into a fly the size of a pony three times per week for 12 hours per use.
Golden lions
Usually found as a pair, these transform into two male Lions once per day for an hour. If slain, they cannot be brought back for a week.
Ivory goats
Usually found as a trio of items. Each one turns into a large Goat with differing abilities.
Jasper Spider
Transforms into a Large monstrous Giant Spider for up to 12 hours. This Spider can be ridden by medium creatures.
Marble elephant
Transforms into an Elephant four times a month for 24 hours per use.
Obsidian steed
Transforms into a lesser type of Nightmare once a week for one continuous use of up to 24 hours. There is a chance it will take good-aligned riders to one of the Lower Planes.
Onyx dog
Transforms into a Mastiff once per week for 6 hours.
Sardonyx stone flyer
Transforms into an adult stone flyer which may be ridden. The stone Flyer persists for up to one hour, each day.
Serpentine owl
Transforms into an Owl or a Giant Owl once per day for 8 continuous hours, however it will only ever transform into the giant owl 3 times.
Silver raven
Transforms into a Raven for 24 hours a week.
Red boar
Transforms into an infernal boar, used as war mount.
Black spider figurine
Transform into a green Giant Spider, called Kitthix, for five minutes once a day. She can use her Web Tangle ability. Kitthix attack is poisonous.
Guenhwyvar is a unique figurine in that the statuette summons its creature rather than transforms into it. This could be due to the strange circumstances of its creation and the uniqueness of the beast, a particularly intelligent and powerful panther. She can be summoned by calling her name to the black onyx figurine, for up to twelve hours of every 48-hour period. Although it is possible for her to be summoned for longer than that or before the cycle of 48 hours begins again, it is very draining and probably unwise to do so. Guenhwyvar also has the power to transport any creature she touches to and from her astral home or to the Ethereal Plane.