Anything. There's some gardeners who sow everything in modules. Ive watched some Charles Dowding videos, no dig gardener, who has some good videos on using those sort of trays.
Yeah I've done my fair share of microgreens, I still think the microgreen peas shoots are the best ones I've done. The sunflower ones were too much of a chore.
I have found the large cell modules are no use for me as I only need small amounts of veg. I tried sowing a variety of veg. in one module but because they germinated at different rates it was difficult to keep those that still need covering going and removing those that need pricking out or potting on. I now use small individual pots stood in a seed tray, then as they come through the pot can be easily lifted from the seed tray and transferred to another tray and grown on without being covered leaving the cover over the seed yet to come through.
Posts
His YouTube channel is excellent, a very knowledgeable chap.
I might try some Mizuna spicy in the modules