5-10yrs til retirement. Over 50 yo
No debt other than taxes, insurance, monthly bills, groceries.

Say one has 1 maxed 401k + catchup
1 maxed IRA + catchup.
2 maxed Roth IRA's + catchup
Collection is insured, have umbrella policy.
savings is building

What other type interest earning investment accts can I put $$$ in?
Say up to 5-9 years

I would get the 10k treasury bond..Its all the rage. Have one myself.

I-bonds

They're all the rage now because the CPI is high.  Eventually that pendulum will swing back, so you just need to keep an eye on the rate.

And yes, I bought some.

Once you're maxxed out on the amount you can shovel into either tax-deferred or tax-exempt accounts, you are maxxed out.  just open a taxable account and snag one of the tax-efficient mutual funds.

if you want to pick the investments yourself, stick to muni's on the fixed income side, and if you're investing in ETFs, mutual funds, or individual equities, avoid short-term capital gains by not selling positions less than 12 months old.

when you're maxxed out, what matters is your investment strategy, because regardless of where you invest, you are going to pay taxes, so your investment strategy should prioritize tax-efficiency and given your age, capital preservation.

I-bonds can be practicable for some investors, however you must open an account directly at treasury (treasurydirect.gov), and you're limited to 10k.

ETA: if you're going to do any muni bonds, check your state's taxation of them.  I think in OK, OK munis are OK income tax-exempt, however munis outside OK are taxable, but double check to be sure

if you're wanting a 5-9 year investment horizon, a muni-bond portfolio is probably most appropriate, without knowing anything else about your goals or risk tolerance.  keep in mind, it's very unlikely the yields will keep up with these elevated inflation rates at the moment.  so you may want to consider pairing a muni-bond portfolio with a high dividend yield equity strategy.  

I was not aware you could max out an ira and a roth ira. thought it was max total for both.

HSA investment account if you are on a high deductible plan. I have tried to convince the wife to use this instead of spending the hsa money.

Im not very knowledgeable about this but i think that if the capitol gains are invested back into real estate they are tax free...

The annual total max (7k with catchup), is the total max for the combined traditional plus Roth IRA contributions per person.

It's a simple IRA. MAX is 12,500 plus ~$3k catchup i think
Roth IRA is $6k plus $1k catchup

Ah, I don't know much about the Simple IRAs.  Sounds like you're aware of the limits.

I started adding ibonds last year.  It's the only holding I have that's on the upside this year.