The Galactic Arecibo L-Band Feed Array H I (GALFA-H I) survey data release 2 (DR2) covers the 21 cm hyperfine transition of Galactic H I from -650 to 650 km s-1, with 0.184 km s-1 channel spacing, 4' angular resolution, and 150 mK rms noise per 1 km s-1 velocity channel. DR2 covers the entirety of the sky available from the William E. Gordon 305 m antenna at Arecibo, from decl. -1deg17' to decl. + 37deg57' across all R.A.: 4 steradians or 32% of the sky. DR2 differs in a number of ways from data release 1, which was released in 2011. DR2 is built from a largely separate set of observations from DR1, which were taken in a much more consistent mode. This consistency, coupled with more careful attention to systematics and more advanced data reduction algorithms, leads to a much higher-quality DR2 data product. We present three data sets for public use: H I data cubes, far-sidelobe stray-radiation-corrected column density maps, and results of the Rolling Hough Transform linear feature detection algorithm. Original acknowledgement for data: We use data from Galactic ALFA HI (GALFA HI) survey data set obtained with the Arecibo L-band Feed Array (ALFA) on the Arecibo 305m telescope. The Arecibo Observatory is operated by SRI International under a cooperative agreement with the National Science Foundation (AST-1100968), and in alliance with Ana G. Mendez-Universidad Metropolitana, and the Universities Space Research Association. The GALFA HI surveys have been funded by the NSF through grants to Columbia University, the University of Wisconsin, and the University of California.