When it comes to self-directed retirement plans, any plan can–generally speaking–be self-directed. That is true whether it is a self-directed Traditional IRA, Roth IRA, SEP IRA or SIMPLE IRA. Whether you have a company-sponsored 401(k) plan or an Individual 401(k) plan–also referred to and marketed as a Uni-K, Solo 401(k) or self-directed 401(k)–they can ALL be self-directed.
While any of these plans can be self-directed, the majority of plans that are self-directed are the Traditional and Roth IRA, along with the Solo 401(k).
Self-directed or not, however, you should consider all of the retirement options that are available to you.