Is it permissible in Islam for someone to pray for themselves to die? Assuming you do nothing to purposefully bring about death on yourself.
No it's not allowed to pray for death on themselves, even though we will all die one day.
The Prophet said =
"None of you should wish for death because of a calamity befalling him; but if he has to wish for death, he should say: 'Allahumma ahini ma kanatil-hayatu khairantli wa tawaffani idha kanatil-wafatu khairanli - O Allah! Keep me alive as long as life is better for me, and let me die if death is better for me.'"
And the wording in Sahih Muslim =
None among you should make a request for death, and do not call for it before it comes, for when any one of you dies, he ceases deeds and the life of a believer is not prolonged but for goodness.