Many rodent species besides squirrels cache smaller fruits, but their activities usually take place at night, so we don't notice them. There are several species of Spanish Needles. The one pictured is Bidens bipinnata , a common weed in eastern North America. The mistletoe strategy is effective because mistletoe fruits are gummy and sticky. This stickiness causes the fruits' tiny seeds to adhere to bird beaks.
Unspecialized fruits can also travel.
Maybe you can remember walking across a muddy lawn, then when you were inside cleaning your shoes you noticed that crabgrass seeds were embedded in the mud. Such tiny seeds as well as spores travel on the muddy feet of other animals, too. It's been found that many kinds of fungal spores travel within the plumage of birds, including migrators, so feather-bound spores can hitch rides for thousands of miles. Even insects carry spores on their bodies, including spores of disease-causing organisms. Dutch elm disease, cucumber wilt, and many other diseases are transmitted this way.