Suspension-feeding animals interact with microplastics of different shapes and sizes suspended in the water column. Bivalve molluscs have been suggested as potential bioindicator species for microplastics as they are known to consume microplastics in the natural environment, are widely distributed, sessile, and easy to collect; however, these molluscs are selective suspension feeders and, thus, do not consume all particles to which they are exposed. This study investigated how three indiscriminate suspension feeders, the Atlantic slippersnail Crepidula fornicata (gastropod), the sea grape Molgula manhattensis (tunicate), and Styela clava (tunicate) interact with microplastics of different sizes, shapes, and polymers to determine their suitability as bioindicator species for microplastics. The data were compared to that of previous experiments with oysters (Crassostrea virginica) and mussels (Mytilus edulis). Animals were offered aged polyester or nylon microfibers of different lengths, nylon, and polyester microfibers of similar lengths, or polyethylene and polystyrene microspheres of similar diameters during a 2-h exposure. Feces and pseudofeces collection during and after the exposures revealed that slippersnails and sea grapes both exhibited size-based rejection of nylon fibers, rejecting longer fibers at higher proportions. Polymer type did not influence ingestion of fibers or spheres. Sea grapes were the most indiscriminate feeders when compared with slippersnails, oysters, and mussels, but were able to egest microplastics just as quickly. Although sea grapes rejected proportionally fewer microplastics than slippersnails, neither species will make an ideal bioindicator because they do not ingest all plastic particles they encounter, they egest the particles quickly, and do not accumulate microplastics in their tissues. Data are currently being analyzed for S. clava exposures to include in this comparison.