I'm compiling a list of things we can know with certainty. The list will grow as I think of more examples.
1. "I think therefore I am." Cliché? Maybe, but it's undoubtedly true. In order to doubt my own existence, I would first have to exist in order to doubt it.
2. The laws of logic, in the form of propositions, are necessary truths. Any denial of the law of non-contradiction, the law of identity, or the law of excluded middle results in a literal absurdity.
3. No potentiality can actualize itself. This is one of the few causal premises that is not just highly plausible, but can be known with certainty. In order for a potentiality to actualize itself, it would have to be self-caused, and therefore exist and not-exist simultaneously, which is contradictory.
4. Order is more fundamental to reality than chaos. Chaos is intelligible, and since intelligibility presupposes order, it follows that even what is perceived as chaotic must have a level of order behind it. One could not even recognize "chaos" if it were utterly devoid of order. Moreover, chaos does not violate any of the laws of logic.
5. If I experience pain or pleasure, then that experience must be genuine. For even supposing that my brain is being manipulated by a mad scientist so that the sensations of pain or pleasure are illusory, it's still the case that I experience pain or pleasure. Likewise, "I am being appeared to redly" must be true, even if the object in question is actually not red at all. In both cases, it is the experience that is certain, which is independent of the reality (which may or may not correspond to one another).