Any waypoint will give you trinket materials. Mushrooms are really, really easy to get (I routinely sell anything over 600 of any single kind of mushroom, definitely do not keep every mushroom you get). This page shows rough estimates for farming the next three levels of ingredients: ★★ (t2), ★★★ (t3), and ★★★★ (t4). If you play long enough, eventually you'll want some ★★★★★ (t5) materials, but they only appear in quantity at the higher waypoints.
These are averages. You may get a lot more or less of any ingredient, but generally you'll get more of those with higher numbers here, and a lot less of those ingredients that are listed as ×2, or aren't even shown at all. The number of runs (samples) is only shown in case anyone cares about statistics.
The primary element for each waypoint is listed first, then each element in descending order of ingredients earned. I'm only listing ingredients that I earned an average of 1.5 or more of. Every number is rounded, because this kind of sampling is very rough, and sometimes you'll be very lucky or very unlucky for a stretch anyway (just like everywhere in DH5).
The hauls are shown as cards, as if you were getting the ingredients in the game, except that I have sorted them by element, and started with the lowest ranks of ingredient. For example, a waypoint that gives you (on average) three t2 light roots, two t2 nature roots, and two t3 light hearts would look like this: