I'd say apple and pear guilds would be closely related.
They have lots of surface feeder roots so you would want things that have deep roots so as not to compete too much. For example, comfrey, artichoke. Interestingly those are the two that came to mind before I looked this up:
Would a Bradford pear fall into the same category as other pear trees? I have a few in my backyard that produce pretty heavy shade currently, though I intend to trim them some. They are in the north end of the lot. Grass doesn't grow under them and the ground slopes down to this section of the yard so that water pools in this area with heavy rains. I would like to plant things that can withstand shade and occasional flooding, although I will try to capture water before it flows here with some swales. This is sort of my zone 2 or 3 that I don't want to involve much maintenance. My dog will most likely be romping around the area as well. I live in hardiness zone 8a in north Texas. Any advice for my situation is much appreciated.
I've been googling shade tolerant plants for the wooded area on my new land. Its pretty shaded there. I can't believe how many shade tolerant options there are that would meet the needs of a guild. I'm in zone 5b/6a so my plant selection won't be the best for you. But I would bet there are many options for 8a that can provide mulch, nutrient accumulators, flowers and food.
Try SightLeveler https://apple.co/2obGUJL, an optical level for your iphone.
SightLeveler can be used to plot contour lines in the landscape for building swales!