The debate around my house on familiars is never-ending. Yes, we all admit they are useful. Yes, they are certainly cool. No, no one has one.
[That is not quite true; two characters have special familiars from a specific spell - I should post that and the unique familiars some day. Or they are in the book Mage Guild already. Very, very broad hint.]
Of course, we aren't alone. While those extra hit points and such are really handy at 1st the idea of taking all those penalties when your toad get's hit with a Fireball is terrifying. WE have a lot of ideas floating around, like; having spell-like rituals that can be researched so that familiars get tougher at 3rd, 5th, 7th, 9th, 12th, etc. levels; higher level variants of Find Familiar that get you tougher familiars or make sure you get a special one; or making magic items for familiars.
That last one led my two oldest sons to think up the Familiar's Hat;
The Familiar's Hat is usually in the style of a capuchon, hennin, or even capirote but may also resemble a kalpak, bashlyk, phrygian cap, dhaka topi, or even a busby or akubra. The hat may be simple or fancy, battered or crisp, plain or embroidered and bejeweled.
Regardless of appearance all Familiar's Hats share the trait of containing an extra-dimensional space meant as a form of dwelling and protection for familiars.
When first found the Familiar's Hat will typically be inactive; the extra-dimensional space will be inchoate and unformed. But when touched by the owner and his familiar at the same time the Familiar's Hat will both assume a specific 'interior' form and both the familiar and owner will be mystically aware of its powers.
Once activated the familiar may enter the hat in one of two ways; they may open a magical 'door' and enter normally or they may be whisked into the hat via a very limited form of teleportation.
When entering normally the familiar opens what appears to be a small, hinged door that appears on the side of the hat. This takes a total of 4 segments and allows the familiar to take things into and out of the extra-dimensional space. The familiar can open the door at any time and may move back at forth at will.
To be whisked into the Hat the familiar must be on or within arm's reach of the owner and the owner must be wearing the hat. The teleportation can be triggered by thought at any time the familiar is not surprised and takes only a segment. The experience of being whisked inside is disorienting and leaves the familiar stunned and disoriented, unable to perform any action for 19 full segments.
When inside the Hat the familiar may still communicate with the owner so long as the owner is wearing the hat. The familiar may see, hear, and communicate otherwise by opening one of 4 'windows', one each to the front, rear, and each side. When opened these windows appear on the surface of the hat and a brief glimpse of the interior and the familiar may be seen. Nothing may be passed through these windows but light and conversation; items and spells (including such things as Charm) are blocked. While inside the Hat the familiar may be harmed by no outside force.
As mentioned earlier the interior of the hat is configured when activated and is based upon the type of familiar as well as the personalities of the familiar and owner. A toad will have a (very) small, moist glade, a raven an open area with a perch, a cat a cozy little den with a few ledges, etc. At the extreme ends an imp or quasit will have a tiny chapel of evil with a miniature altar and a brownie will have a snug miniature cottage complete with a fireplace. The owner may place nothing into the Hat directly, all will have to be taken in with the familiar directly or indirectly; the toad may be accompanied by insect and such, 'stocking up' the Hat with food while the brownie may take in tiny furniture, firewood, etc. The Hat cannot be used as another extra-dimensional storage space for loot, etc., unless it is the property of the familiar.
The hat will always have an encumbrance of 3 lbs. It makes all saving throws as the best possible material and at +3. If the Hat fails a saving throw it is destroyed and, if inside, the familiar is immediately ejected; in this case the familiar is unharmed but is stunned for 3 rounds.