Moving onto water-based food supplies:
Each of these tables are deliberately simple for the present - they can be expanded for later ideas having to do with potential food supplies. I'm just tossing out what occurs to me - and at the same time, adding features that may have nothing to do with food, such as the 'dead pond.' A dead pond is a place where salt or other minerals have rendered the water undrinkable. That will probably become a stub at some point in the future that designates a certain creature that might dwell there or be associated with it.
Banks are related to salt water. They may also be called shoals, places where fish congregate due to food supply. Cool or cold sea water is created by currents, inspiring bacteria growth that in turn encourages spawning and schooling among larger fish. Not every sea hex is a bank; the local fishermen come to know where to fish, so that there might be adventurous fishing folk temporarily in a hex that is considered 'wilderness.'
Dried ponds have little or no standing water are still fed by groundwater, so that they feature green grasses, rabbits, grouse and other small game, as well as hay for animals. Seasonally they will form sloughs, standing water that is anywhere from an inch to a foot deep - these will evaporate slowly, as groundwater is usually just below the surface.
Fishing ponds are fed by brooks or creeks, or may be formed by groundwater springs (not to be confused with aquifers, a rare form of geological groundwater formation). These may be naturally possessed of fish or they may have been stocked by locals. Water tends to be from 3 to 10 feet deep (or more, depending upon the topography). I have written some rules about fishing on the wiki.
Hot springs occur in mountain areas (and rarely elsewhere). Oases form in deserts - and are really only special because they're springs that occur where there's no water. However, they do tend to be intensely employed for that reason, so that a single oasis would likely produce more food than a dozen springs in a temperate clime (where they would be ignored).
Pingo pools and hills are fascinating. I was surprised to find that the pools sometimes contain fish; this is due to periods of flooding, so that fish are left behind after the nearby river recedes.
The base chance for a bank is 2 on 3d4, modified as follows: +2 for coast, +3 for a river mouth, +1 for open sea. This means that the chance indicated will be impossible unless the sea touches upon the hex - which is fine, since in those cases a 'bank' cannot occur in a mainland hex.
The base chance for a dead pond is 2 in 2d4 in subtropical dry climates and 4 in 2d4 in temperate dry climates. Dead ponds do not occur in other climates.
The chance for a fishing pond is 2 in 2d4, modified as follows: -1 in mountains, +2 if a river, +3 if a river mouth, +4 if a swamp, +3 in tropical wet climates, -1 in subtropical dry climates, +1 in temperate wet climates. Dried ponds occur if the chance for a fishing pond is missed by 1. Thus, if the chance of a fish pond is 2 and a 3 is rolled (as is the case with Hex C above) then a dried pond exists.
Hot springs have a 1 in 100 chance of occurring in mountains. (Non-random hotsprings occur in my world where designated by wikipedia - benefits of running the real world).
Oases occur on a 3 or 4 rolled on 3d6 in desert hexes.
Pingo pools occur on a 2 to 4 on 2d4 in subarctic conditions (north of the tree-line). Pingo hills occur if the chance for a pool is missed by 1 (like dried ponds).