Death is one of the most important topics for recollection, which has an immense potential in terms of fostering practice and developing letting go. Anything that we do or try to appropriate is based on the fact that we are alive. But life belongs to nobody and cannot be appropriated. One who relinquishes appropriation towards life weakens appropriation towards anything else.
This practice of death recollection comes up in various discourses:
(1) Death is sometimes introduced as a 'divine messenger' that reminds people of some fundamental facts about life: in AN 3.36 it is presented in the context of rebirth, while in AN 3.39 it is part of the Buddha's own story. In more poetical and perhaps dramatic terms, see also SN 3.25.
(2) For this reason, death is also considered to be a powerful motive for first reflecting on the inherent uncertainty of life, and then finding a sense of urgency towards having to do something about it. Concerning the first, see e.g. AN 5.48, while for the urgency see e.g. AN 6.20.
(3) Recollecting death is also taken up as a more formal meditative practice, as a deliberate commitment to keep paying attention to the fact that life is uncertain from moment to moment. This is made explicit in AN 6.19, and appears less explicitly in the Satipatthana Sutta (MN 10), in the second on the recollection of corpse decomposition.
(4) This form of recollection, is then explicitly mentioned in AN 5.57 (see the Introduction to Friendliness §4) as a core theme for uninterrupted reflection, which leads to the 'arising of the path.' In AN 5.57, meditation on death is more explicitly linked with friendliness and compassion (or non-aversion), but also with the recognition that it applies to all living beings, and hence it makes no sense to seek just another form of life, since the problem will be there anyway. The arising of the path is usually explained as a profound understanding of what the Buddha presents in the discourse on the 'four noble truths' (SN 56.11), in which death is included as one of the indications of suffering in the first noble truth.
Plenty to choose from. No time to waste!