Sure!
Lembas - Specially crafted cakes, made using a secret recipe of the elves. Requires 5gp worth of ingredients suitable for healing rituals. Keeps up to 6 months. You can gain the benefits of a long rest with only four hours, 2 of which must be spent sleeping.
Rock Rations - Leave it to a dwarf to figure out how to make a rock edible, but don't count on it tasting good! Keeps forever (some have been known to be good after 1000's of years of storage). Gain an extra hit point each time you take a short rest after eating one meal of these, until your next long rest. Requires 5g worth of ingredients suitable for arcane rituals.
Gorp - Certain human tribes and frontierswomen (lets face it, it was the women that figured this out) have developed a recipe of dried fruits picked only from specific blessed bushes, honey, and wild grains. It requires 5gp worth of ritual components to make this. Once per day when you spend a surge to gain healing, heal an extra 1d6 hit points. Gain a +1 bonus to one death save each day.
Each of these, and others may exist of course, require half a day to prepare and serve as an entire day's worth of rations, at a weight of 1/4 pound. The formula for each one is considered to be a Martial Practice, and costs 125gp to learn, assuming you can find someone willing to share such knowledge, as it isn't given freely, especially to members of other races or groups.
While such goods are almost never sold on the market, they may be procured from allies or discovered in storage or in someone's equipment.
Additional possibilities
Orcish blood wine (hey, they had it first, the Klingons ripped it off!), kobold dried fungus, gnomish cakes, halfling pipe weed, etc. Warriors and adventurers of these races may be equipped with these materials, and they might fall into the hands of PCs now and then, though differences in physiology between humans and other races might cause some difficulties.
