Quality inspection of candidate galaxies. From left to right the three columns correspond to: (1) close-up SDSS image of the candidate galaxy. In all cases the box has a size of 1.8′ × 1.8′. North is up and East is to the left. (2) SDSS image of the broader area surrounding the candidate galaxy. Each box is 7.4′ × 7.4′ in size, such that two ALFALFA beams could approximately fit side by side in the box. Red squares denote spectroscopic objects in the SDSS database, while arrows indicate potential blends. (3) ALFALFA spectrum of the HI line for each candidate galaxy. The x-axis corresponds to heliocentric velocity and has a fixed range of 1800km s^-1 in all panels. The y-axis corresponds to flux density and its range varies from panel to panel. The annotated score refers to the subjective quality score described in item 4, with a maximum value of 20. Galaxies with scores lower than 17 are eliminated from the final sample. Comments on individual galaxies (from top to bottom) follow below. AGC 191770: this galaxy has a perfect quality score. There are no companions around the galaxy and its HI line spectrum has no flaws. AGC 7326: this galaxy lies at a heliocentric velocity of −167km s^-1, and its HI profile slightly overlaps with Galactic HI emission (visible as a subtraction artifact in the HI spectrum). However, the measurement of the HI width and flux for this specific galaxy was deemed reliable enough to be granted inclusion in the final sample. AGC 724093: this galaxy has a probable dwarf companion about 1′ to its West. Given that the companion is much dimmer than our target galaxy and that the physical association of the companion is not certain (the companion lacks an SDSS spectrum), the main target galaxy was nonetheless included in the final sample. AGC 253926: this galaxy has a spectroscopically confirmed companion that lies about 1′ to its southeast, and is only slightly dimmer than the central galaxy. AGC 725127: the spectrum of this galaxy has a peculiar shape, with several peaks and a broad wing in the blueshifted edge of the profile.