The phrase "limitless number" means that there is no end or boundary to the amount or quantity being referred to. It suggests that there is an infinite or endless supply or quantity. Full definition
As you can see in the image (one the door panel), the seats are adjustable in an almost limitless number of ways. (bestride.com)
In actuality, social media enables the formation and maintenance of an almost limitless number of smaller communities, each organized around a relatively narrow theme. (entrepreneur.com)
With limited resources pitted against a seemingly limitless number of ways to produce terror, we will probably always be chasing a moving target. (discovermagazine.com)