I think it varies from locality and seasons. In my area, Khyber Pakhtunkhwa, Pakistan apis mellifera highly forage Ziziphus especially Ziziphus jujuba.
A lot of protein patties are existing now in the market, but often locally produced and not so evident to buy.
If you want to produce it by yourself, the general idea is to make a patty with rather high protein content (16-20% calculated on dry matter) and to put it in contact with the brood nest so that nurse bees can directly consume it. To reach this amount of protein content, you need to use higt proteic sources, like leguminosae flour (soja, peas, etc) or yeast.
You may use at least 10% of pollen (from healthy colonies) to mix with your proteic source, as pollen contains some attractive substances inciting bees to consume it. Mix pollen and proteic source with some syrup and water to get a correct consistency.
Put 50g to 200g by colony each week when necessary, but verify that the bees consumed it, as they always prefer fresh pollen of their own instead of patties.
Honey pollinators are available in forest tree's in during death period in forest tree's resembles tamarind species are in death period pollinators (garden plants like roses etc )