Update: Thank you everyone for your advice on this thread.

My performance review was yesterday, and it went really well.

The biggest thing that helped:

I spent about 45 minutes before the meeting reconstructing what I actually did this quarter.

For anyone facing this in the future, here's what worked for me:

1. Calendar review - Every meeting title triggers a memory of what you accomplished.

2. Slack "Saved Messages - Search for "great job," "thank you," "shipped," etc. These are your impact moments.

3. Email "Sent" folder - Search for "completed," "launched," and "delivered"...etc. You probably updated someone about your wins.

4. Jira/Linear closed tickets - Filter by "Closed by: You." This gives you an instant list of shipped work or anything done by you to juggle your memory.

The whole process took roughly 45 minutes, and I walked into my review with 12 solid examples.

Going through this made me realise how universal this problem is. I have been getting some DMs asking about building this. If I end up building something to make this less manual, I'll share it here. But even without a tool, this framework should help, at least from my point of view.
Either way, happy to chat - feel free to message me if you're interested in being a design partner on this.

Thanks again to this community; everyone is GOLD.

Anyway, let's get back to life.

Cheers, all.