Familiars are magical creatures that act as companions for witches and spellcasters in The Sims 2: Apartment Life (when The Sims 2: Pets is also installed) and The Sims 4: Realm of Magic. Witches in The Sims 3: Supernatural get a moodlet that boosts spellcasting if they own a cat or a small pet, but these pets are completely normal otherwise.
The Sims 2: Apartment Life
If players also have Pets installed, witches can summon their own cat familiar called a spectral cat.
The Sims 4: Realm of Magic
In Realm of Magic, spellcasters can acquire magical familiars that can aid in spellcasting. If players own Cats & Dogs, their pets can be bound as familiars as well.  Spellcaster children can also own one, though they are unable to do magic until they grow up.
List of familiars
|Bunnerfly||This interesting creature is an unexpected entity that defies normal boundaries and demands a closer inspection. Its true nature is unknown.||Common|
|Dragon||Regal and powerful, this dragon should never be discounted based on its size. It is a formidable foe as well as a cherished companion.||Uncommon|
|Fairy||Bathed in pure energy it is nigh impossible to make out the true form of a fairy beyond its magical wings. One can feel what can only be described as a slight spark when near.||Common|
|Glowfrog||Be warned to avoid the direct gaze of the glowfrog. They are usually quite mischievous characters although quite harmless when left to their own devices.||Uncommon|
|Hex Doll||Despite this familiar being the mysterious and silent type you may still catch yourself whispering to them, "Do that voodoo that you do!"||Uncommon|
|Leafbat||A classic Spellcaster companion, bats have commonly been closely associated to magic users since the times of ancients.||Uncommon|
|Phoenix||The Phoenix is intimately familiar with the cycle of life, death, and rebirth. From the ashes they arise and into the ashes they fall. So has it always been.||Rare|
|Raven||The harbingers of prophecy and, some say, bad luck. Ravens are an ancient creature that remain steadfast alongside their favorite Spellcasters.||Common|
|Sixam Owl||The preeminent symbol of magic and ancient knowledge. They have a strong connection to the moon and stoically follow their chosen Spellcaster.||Common|
|Skull||When you need a protector that truly frightens your opponent consider the skull. It is hard not to be intimidated by this floating, haunting familiar.||Rare|
|Veild||The Veild is a Voidcritter deep with the knowledge of countless galaxies across space and time. No one really knows the true motivation of this critter, but that didn't stop one well known kids TV show from almost featuring the Veild as a main character.||Rare|
Familiars are extremely helpful to spellcasters. They have magical energy reserves, aid spellcasters in magic duels, and can even protect them from death. Familiars must rest to regain their power after saving their owner's life. Cats and dogs (and by extension, raccoons and foxes) can be sent to forage for magical items.
- The fairy's appearance and one of its randomized names, "Hey", is a possible reference to Navi from The Legend of Zelda, a small glowing fairy who is known for saying "Hey! Listen!" to get the player's attention.
- While the leafbat isn’t a real creature, they’re most likely based off/closely resembles the Honduran White Bat.