Fun, I have a perfect thing for this!
I have slowly over the last few years set aside volunteers that i find in my pots, flower baskets and elsewhere on my property. Usually these are from the massive Douglas Fir, redwood, mountain ash or native willows I have on the property. A few weeks ago I finally sorted a handful of redwood? Into a forest arraignment with the plan of continuing to add more as the years go on to increase the age and size difference represented.
I plan to do a few more forests, I have a few flats full of strange mystery sprouts and seedling volunteers. So I may go in a few directions for the first year and see which ones excite me further on.