Ever since the discovery of carbon nanotubes (CNTs), it has long been a challenging goal to create macroscopically ordered assemblies, or crystals, of CNTs that preserve extraordinary properties of individual CNTs on a macroscopic scale. Recently, a method to fabricate wafer-scale aligned CNT films via controlled vacuum filtration and a method to produce fibers of aligned CNTs through solution spinning have been developed. We first discuss parameters behind CNT alignment formation during vacuum filtration. We found that parallel grooves pre-existing on the surface of the filter membrane dictates the direction of the resulting CNT alignment, and further developed a method to imprint periodically spaced parallel grooves. We then discuss the thermoelectric properties of aligned CNT fibers. Thanks to the ultra-high electrical conductivity, we observed the highest p-type power factor at room temperature. Our finding provides a route for a powerful, mechanically robust, light weight, and non-toxic wearable thermoelectric devices.