This article in Forbes describes a not very well known rule that allows an early retiree to access tax-advantaged retirement funds at 55 instead of 59 1/2. You can access the funds in the 401(k) (or analogous) plan of your last employer if you’ve left that job and are not working. So you could do a reverse rollover of your IRA into your employer’s 401(k) account, then leave your job and access all that money penalty-free.
A side effect of that reverse rollover would be that if you have no money in a traditional IRA, you can make a post-tax IRA contribution and roll it over to a Roth IRA tax-free.