All three categories of tadhkīr aim to remind and admonish, but they differ in their immediate focus.
Divine favors: signs and benefits in the present world, such as rain and provision.
Days of Allah: salient events of divine support or judgment in history, such as the outcome of a prophetic community.
Death and afterlife: the end of life and accountability beyond it, such as resurrection and reckoning.
A longer passage may employ more than one theme. Classification should attend to the dominant purpose of the verses under study instead of assuming rigid mutual exclusivity.