I retired in February but went on a sabbatical before that, so my last work day was some time in November.
While on sabbatical, I still accrued vacation days, kept my stock options, got to use the employee gym, and kept my employer health insurance.
I was also able to retire directly from my sabbatical, so I could (a) test drive FIRE for a few months, and (b) avoid any awkward-for-me going-away stuff.
I was due back in the office on a Monday. The Thursday two-plus weeks previous to that, I exercised all of my stock options. The day after I submitted my two week notice and sent a goodbye email to my colleagues.