I'm in a very similar situation (at our FI number of $1.3M, I'm still working FT for a year, DW is PT). We're also basically in a 3 fund portfolio (more int equity than you and less bond).
If anything, I've been tending towards simplicity in recent years. We used to do a bit of peer to peer lending, but I've gotten out of that. We use to have 5% in REIT, but I've gotten out of that. We used to have a sliver in precious metals and mining (via a mutual fund) but I've gotten out of that.
For us, now, I think the change will be to increase our cash holding -- we recently moved to Canada, so our expenses are here, but all of our investments are in USD. Thus, I'd like to have a cash cushion to both moderate swings in the exchange rate AND in the market. We're both earning CAD right now, so it isn't a priority, but as we work less I think I'd like to have a cash cushion in CAD that (along with our PT earnings) would cover ~2 years. And we might also have a separate cash cushion in USD that we could leverage in times when the exchange rate was particularly good. Basically, I'm thinking that instead of being 90/10 stocks/bonds, we'd be more like 80/10/10 with the last 10 being cash. It depends how much were working, though. If our part-time work is close to covering our expenses (which it likely would be) I don't know that I'd bother with much additional cash.
I'm not interested in gold or crypto (I may just be dumb, but they don't have any inherent value to me). I am going to be picking some individual stocks, but that's because I have Canadian money to invest and individual stocks avoid PFIC requirements. Otherwise, I wouldn't. I wouldn't "invest" in things like art / cars / baseball cards. Beans is tempting -- honestly. I think getting good at gardening, DIY, building community relationships is probably the best kind of diversification.