Think of food delicacies from Canaan in Burqin, think of plastic chairs from Royal in Hebron, think of Shoes from Falcon, think of diary products by Juneidi, think of matresses by Herbawi, think of furniture from Eisa Mohana Co. in Gaza, medjoul dates by Al Nahkeel farm, bell peppers by Sinokrot, turkey breast by Siniora, and many more. Further recommendations? Comment below!
Trust in Labels
A label without trust is worth nothing. Palestinian customers typically rely on word of mouth (e.g. recommendations of their neighbor), and on opinion leadership (statements of trusted, famous personalities). In addition, compliance labels to international standards (ISO, CE, DIN, etc.) would create trust, but they certify compliance with formal requirements such as material and chemical properties only, not evaluating overall product quality from customer's perspective.
A label would need to make sure its financial independence, and needs to be under the auspices of a trustworthy personality. Criteria for receiving the label, and revoking the label need to be clear and transparent.
Since you are promoting domestic products, and addressing an audience that possibly likes to promote the Palestinian cause, a design that includes some elements of kuffieh or embroidery patterns or such, is probably not a bad idea.
The Business Model
To avoid bias in awarding your label, you should charge for a product to be tested, and the supplier needs to pay in advance, regardless of the outcome of the test. If the product passed the test, the producer is allowed to carry the label for a defined duration of time, and he can print your label onto the product.
Include the possibility of revoking the label in the contract.
To get things going in the beginning you can offer at least one product test for each producer for free. Each type of product requires different test criteria, so don't try to start with all product types at once.
Check Best Practices
Europeans love product tests and labels, so get inspired by their huge diversity of different labels. Some are completely private, some are in compliance to some law, or some technical standard. Also look for customer-centered evaluation criteria as used by Stiftung Warentest for example.