We present experimental results and designs of large-absorber transition-edge-sensor (TES) X-ray microcalorimeters. Much of our effort has focused on developing close-packed arrays of 250 - 300 μm-sized pixels suitable for the X-ray Microcalorimeter Spectrometer (XMS) on the International X-ray Observatory. These efforts have produced devices with the requisite energy resolution of ≲ 2.5 eV (FWHM) at 6 keV. There are several upcoming applications, however, that require arrays composed of significantly larger pixels. In this contribution we present experimental results from 490 μm-sized pixels that have attained 3.5 eV energy resolution at 6 keV. These devices are precursors to the pixels that are being developed for the XMS extended array. In addition, we briefly describe detector designs for the Micro-X sounding rocket experiment, which also requires an array of large-area TES microcalorimeters.