So based on your 2d reply, you're getting about 4% on your money (i.e. $36,000 net income on a $1,000,000 property). This is fairly low for income property AND of course it's unpredictable. there will be years, like you've already had, where you need to spend some of that 36K on extra capital improvements / unexpected repairs / vacancies, etc. Plus it can be time consuming. Assuming you already have enough in your current portfolios, you could do one of the following:
1. Distribute it among your current investments. Because this is the most boring sounding strategy, it's probably the best!
2. Foray into other RE type investments. There are some well reviewed Peer to Peer RE opportunities out there. I plan on putting some funds into a couple of them in the next couple of years. Here's a link to some reviews:
https://investorjunkie.com/47367/p2p-real-estate-crowdfunding-comparison/
3. You could do "hard money lending" to RE investors. You can make 8-12% on your money. Of course you'll need to lend $40-$200,000 in one chunk so it's hard to spread your risk. HML is quite lucrative though and some people literally do it for a living.
4. Put the bulk of it in fairly safe, boring investments but take $100,000 and move it into riskier things that despite their risk, pose a good chance of taking off. There's "Angel Investing Funds" now. I made $36,000 on a $2,000 investment recently in bitcoin and 2 other crytpo currencies. What I do is simply take a VERY SMALL % of my money and put 1-3K into things that COULD go to zero but also stand at least a decent chance of going up 1000% of more. The secret is diversification, AND making sure each and every micro investment at least stands a chance. This is NOT gambling when you look at it via a macro view. You wouldn't just put half your money on bitcoin but you might put 2K each into the top 6 crypotcurrencies, then 2-3K into 15 different angel investing themes, etc. Most of them could go to zero but if 1 goes up 1,000% you're a hero.
5. What I personally would do: I already know what I'd do with an extra million and that's to purchase property overseas. Colombia, Ecuador, Panama. Perhaps even an oceanfront condo here in Maine in Boothbay Harbor or OOB. Whether you use it as a VRBO unit or not is up to you.
6. Think of the "probable" direction of interest rates and inflation (i.e. up on both) and think of the outlook for investing styles (high dividend, value style is predicted to edge out growth style and this is very probable due to its underperfomance in recent history). Then some "alternative" asset classes to buffer your portfolio. Call it your "tilt portfolio". Keep in mind that it's designed to buffer losses from your main money, so try not to get discouraged when your main portfolio is doing great but my proposed mix is doing horribly. You'd put fairly equal amounts into:
a. MLP's (mostly energy)
b. Preferred stock closed end funds, but ONLY those that have a steeper discount than their 3 year avearage
c. Small company value fund (vanguard)
d. precious metals (no more than 5% of your mil)
e. BDC's (business development companies)
f. Funds that invest in bank debt, where the interest rate rises when general rates rise. This buffers the effects of rising rates (Pimco has a couple of great ones!)
g. MORTGAGE REITS. I hold MORT myself. This is a reit which invests in mortgages NOT real estate.
h. ETFs that invest in the 2-3 worst performing countries over the past 1-2 years. (I'm holding GREK and RSXJ, for example)
f. Farmland or timber ETF's.