RoM Familiars?

Having an active Familiar can spare you death by overload. Possibly death in general, but it's not something I've tested (nor plan to). Saving your sim from death has a one week cooldown, or at least so I've read. Again, Haven't had a chance to test, don't plan to.

They also seem to help when studying magic and with keeping charge manageable. Both are passive effects, so I'm just going based on observation.

Cat and dog familiars can also go scavenge for spell ingredients, brooms, or wands.

The orb ones don't do much, true, but some of their quips when you brew a potion or learn a new spell can be cute/funny. And they seem to have different personalities, and not necessarily based on what type of familiar they are.

The orb ones can also provide you with materials! So far they all seem to be things (fish, plants, and metals) used in potions. That's pretty useful! As far as I've seen, my cat familiar has only picked up that one broom over and over again.

Thank you so much. They do sound actually useful so I will make sure my spell casters have them. :)

You honestly don't need them, and they can even end up lagging behind your Sim so your Sim just stand there waiting for it to unlag so it can do what you planned to do with your Sim. Noticed this can happen when running through some stairs.

Resources are just not needed for the spellcaster, you get a potion as soon as you discover them and with a nice shelf system you plop all potions on there and then just cast the copy paste spell directly on that potion on the shelf and you'll get a new potion to use immediately without having to clutter up the already hopelessly cluttered inventory any more. No need to brew at all. Granted you can avoid the spell and play more normal and then of course resources come in handy, but the spell is always there to tempt you, stay strong ;)

That spell is horrible for gameplay, in my opinion.