But why are these things always available? Other than the fact that they are a cornerstone of the genre... Treasure is another measure of power, just like XP, a bit more fluid, but a direct measurement of the characters power. But what other types of treasure might populate the DM's notes?
Pets/Followers - From a pet panther named Gwenhwyvar, to a little Kobold showing you the way through the mountain, pet's and followers can be found in all manner of Fantasy RPG's. The services and combat utility they offer are probably the most directly beneficial to the adventurers. Companion characters/cohorts also fall into this category, often complimenting the player's combat ability.
Possessions/Holdings - A mountain stronghold, the sacred texts of the sun god. These sorts of treasures may not be very useful for bashing the ogres skull in, but they can open up story routes that would have otherwise been closed. As long as these sorts of treasures don't cut too deep into the players budgets, they can really help drive a story forward. It is also possible for these places to grant material benefits on a players character sheet. Keeping up your training within a personal archery range, or studying texts in your library can grant small bonuses to a characters attack and damage without edging out weapons and other equipment.
Access to Resources - Ancient Libraries, the Great Smithy of the Dwarves. These treasures are great rewards for plot arc's. They give the players a big bonus, something the Bards can sing about, but without unbalancing the economy with a massive lump-sum of gold. Giving the players a resource at the end of an Arc can see the players returning there during future adventure's, and become a good source of plot hooks. Be sure to let the characters use this resource in following adventures. If the players are constantly fighting back local goblin uprisings, perhaps that library has a tome regarding the weaknesses of goblin combat techniques, or the Smithy has blueprints for a Sting-style blade which aids against goblins.
Political Support/Army - Need to get into the Lord Lich's Fortress of Darkness? Have a troublesome army of Orc's in the way? Time to call in a favor from the King of Castle Orledin to march his knights against the darkness. Support from a powerful third party brings more options to the table, and players love options.
I hope this helps you add a little more variety to the rewards for your next adventure.