Alternatives to IRA when income is too high?

Hello!

I am looking for some advice on retirement accounts and tax deductible accounts. I currently work full time (~170k) and generally bring in an additional 75k or so per year doing freelance work. This would put our families total income around 250k ( I am married, but spouse takes care of the kids).

I currently max out my employer's 401k as much as they allow me to (15k + their 6% contribution). I also have a solo 401k that I used for my freelance work income last year. This year I am hoping to bring my freelance net operating income down to 0 if possible (under section 179). If I do this, I would not be able to contribute to my solo 401k and from what I read, I would make too much to contribute to a traditional IRA.

Which leads me to my question... are there any other tax deductible account types I can look into to sink about 10k in before the tax deadline?

Thank you!