Elephant

AD&D ELEPHANT
As one would expect, an elephant is amighty beast with 10-12 HD (Asiatic, African, and Mammoths being the size scale). They have 5 attacks, but must spread them out among targets, as one cannot trample, trunk-squeeze, and tusk-gore one person with all their parts at once. They can wreck gates unless the gate is spiked, and fear fire. Their tusks are worth 100-600gp each, which given the danger involved in fighting one (let alone the numbers appearing of 1d20) is certainly not worth the risk to most adventurers. When 10+ are rolled, 1d4 will be immature members that are 20-70% mature. When a single beast is rolled, it is assumed to be a rogue male with a minimum 6HP per HD, in a state of musth and as such is highly aggressive, attacking 90% of the time (musth is not mentioned but it seems the obvious explanation).

BFRPG ELEPHANT
 Slightly less dangerous, damage output wise, and having a handy entry of how much they can carry (about 4 tons for a light load and 8 tons for a heavy load) as well as giving tusk value at 100-800gp value, this entry sees them more as beasts of burden than combat/war encounters compared to D&D.

3.5 ELEPHANT
Within the animal subcategory of the book, these elephants give a save for half damage to avoid the trample, and have the usual sort of HP bloat to be expected, having not just 11HD, but 11d8+55 HP!

There's a bit of an issue, I've found, with using elephants as a loot source or other exploitable resource- a bleed-over from the sympathy towards the fate of these intelligent animals at the hands of humans in the real world. Similar to beating watch dogs to death, or eating dolphins (tho honestly I almost feel like the opinion on sharks and dolphins is reversing as people learn more about them) pretend elephant hunting can leave a bad taste in some people's mouths when you're lowkey wondering if they'll go extinct in the next hundred years or not. Monsters are the 'acceptable big game' animal in D&D, so having elephants seems redundant and potentially sad in some ways.

telling your apprentices that a elephant skeleton is a cyclops skeleton is a classic joke among necromancers

SUNSET REALM ELEPHANT
While there are Berserkers and Boarserkers, Elephants have totemic berserkers too among the people of Saresare and Yuba, and also the Gondazong people of the fault. Before the cultural melting pot of the north fault, elephant berserkers would have mostly been from the Yoza Invader Barbarians and the Pudizong, and before the migrations and gene-plagues, the berserkers were the Tuskers, dune-dwarves of ill temper and surface living, and before them, in the burning age of Yg-A, there were the Elves who had kinship with the beasts of the land and were clad in ivory and blood and ash and rode elephants so that they could more easily leap onto dragons to slay them and also too to trample the ghul hordes into the ash. Before them was the Serpent Empire which was far too cool-blooded to have any berserkers, and so ends the traceable lineage of Elephant Style.

However, while bears stalk the world round, and boars are sliding towards domestication as pigs(which some say explains why bears remain the more popular berserker emblem), elephants met a different fate altogether.
Elephants once were among the greatest beasts of the land, but now live only in domestication(Saresare and Yuba) or in undeath (The Fault). This is the fault not of ivory hunters, but necromancers, who saw in the elephant a beast that was vulnerable to magically aided hunting strategies, made for a terrifying undead warbeast, and came with built-in treasure/magical components in the form of their ivory tusks. The Deadlieges of the Fault ride atop these undead monstrosities, each rune-carved tusk acting as a magical wand to channel power through, and even forgotten elephant bones rise when Corpse-Bees build their hives in the ribcages of these beasts.

In Saresare, they are status symbols of the sultans and princes and so on, for they require prodigious amounts of water and feed in those dry lands, and are only rarely ridden upon in howdahs usually to stand out from camel-howdahs in urban processions. Back in the 4th age when there was more outright war, Saresare adopted war-elephant tactics from Yuba briefly, but this did not last.

In Yuba, the smaller jungle elephants are somewhat common as beasts of burden and some war-elephants remain, but many perished in the Riikhite crusades of the 4th solar age, and were mummified and sealed away in the pyramid tombs of Yuba. With the death of the Horse God of Yuba, elephants made somewhat of a comeback, but seem to grow smaller with every generation.

It is rumored that in distant, Winter-frozen Moonlands, the great woolly mammoths still walk the earth, and miniature elephants can yet be found on isolated Beast Islands.

Elephants are symbolic of the weight of harsh truths in the realms. They were known to be intelligent creatures, yet unlike most animals which reincarnate over and over again in a perpetual circle of life, the souls of elephants depart the world upon death and do not return, meaning necromancers must animate the bones via slightly more esoteric means than usual.