It sounds more like you’re asking for creative terms for irrevocable testamentary trusts created at death (can be worded in a will just as easily as a revocable trust).

My favorite clause of all time, and I find myself using it more and more, are “incentive” trust terms to encourage beneficiaries to follow their career dreams without as much financial burden. In addition to ordinary distribution language, it’s sometimes helpful to “match” a dollar of income with a dollar of distribution from the trust. A 40k/yr teacher’s salary suddenly becomes 80k/yr (actually a lot more than that, as up to half wouldn’t necessarily be subject to income taxes). I find this language particularly helpful when you have similarly situated beneficiaries with radically different earning potential (say two kids, one’s an engineer the other is a line cook) as well as younger adults the planner wants to encourage to seek employment.

Begging distribution to (M)AGI of the beneficiary can be a really fun and powerful planning tool.