Exit interview will be done in person if they want, also you’ll get an email later to do it. Pension idk I quit before I had one. 401k ensure you have a login set up that you can use, you can keep the account if you want or transfer it to your next job (potentially, depends on their plan) or transfer it to a personal IRA (no penalties or taxes if you transfer Roth to Roth or non Roth to non Roth. Call an advisor they’ll walk you through it). Benefits end date depends on your plan and some other things, call them to ask for your specific case.
Other things to do are to ensure you have any personal info sent to your personal email. Get copies of proof of work, your W2s as far back as you may need, and make sure your contact info is up to date. I’d also include any HR or manager emails you get specific about your personal performance or any situations that happened just so you have a copy of emails of incidents. Lastly scan goto/hr for any documents you find remotely interesting or related to your situation.
Write your goodbye email early and have a list of who you want to send it to early. I did it the last day and I left off a few people that I probably shouldn’t have that I didn’t think about and slightly regret it. Also email yourself their emails, as its useful having it (or include a link to social media of your choice for them to follow/friend you on).
If you like your teammates ask them what they need from you to help them out when you’re gone.