I have used a million different kits with a different mix of things included and while I have my favorites, I can make most kits work as long as they have these 3 things:
1. A balanced mix of flat (labels, tape, paper pieces, paint, word art etc.) and textural elements (flowers, foliage, ribbon, string, buttons etc.). Too many flat elements makes it hard to layer and cluster nicely. Too many textural elements makes the page feel like it's missing something.
2. Papers with small patterns or tone-on-tone colors. A bunch of multi-colored busy big patterns makes it hard to scrap. I actually prefer scrapping with the 'boring' papers.
3. A color scheme with contrast. When all the colors mush together it makes the page feel blah. I like color schemes with both light and dark colors for contrast.