Split into grid (slice paths/shapes into separate objects)
I use Illustrator's split into grid in almost every session. It's brilliant, and although I see you are working in a lot of automatic gutter / guide / spacing assistance in XD, i'd love to see this feature.
Great for making the first instance of repeat grid items that XD then repeats so well.
It could be simplified, but the functionality is priceless!!
This is not the perfect solution, but one tip is to use the grid to creat a model and you can create top on that grid
Adding a divide option to XD's pathfinder (same functionality as AI's pathfinder) would be really nice for doing things like creating grids that have different states, data tables, and for complex accordions.