There are a variety of synonyms for the word "cartloads" that can be used to describe a large quantity of items being transported on a cart or other vehicle. Some possible words to use include "loads," "bundles," "piles," "heaps," "plenty," "abundance," "rennet," "collections," "stockpiles," "masses," "mountains," "clusters," "clusters," and "stacks." Depending on the context and tone of the sentence, different synonyms may be more appropriate than others. Overall, using synonyms effectively can help to add depth and variety to a piece of writing, while also conveying meaning and emphasizing important points.