One suggestion would be to look at the small cross stitch KITS that ECS offers, you might have some success there. If you are not into doing kits ....
you might want to consider looking at a favorite subject you would like to stitch; for example "snowmen" and entering that word into the "search for" box. Once all the charts come up, look through them and pick out ones you like that look like they don't have a lot of different colors to them, THEN go to that chart and look at "project specifications" or if the floss colors are listed, count how many floss colors there are for that chart.

I don't know how few colors you want. If I wanted to lessen cost and speed up finishing, I would pick a subject/theme (for instance, dogs), look at the little thumbnail sketches and it is easy to tell single color or double colors, I think..and I have poor eyesight!
I am not an employee of ECS, just an old stitcher who saw your question