The singular most convenient way to farm Gald in Tales of Arise is to mine, mine, and mine some more. There is no better way to get Gald when you need it than to suck it up and smack a bunch of rocks.
Alternatively, if you don't want to spend your life running in circles punching blue crystals, fishing can net you a pretty penny.
Pretty rocks are worth a lot
Mining can occasionally give you certain commodities instead of those accessory materials that you usually want. These commodities are Iron Chunks, Copper Chunks, Silver Chunks, Gold Chunks, and Platinum Chunks. Your ability to get the rarer chunks is dependant on your story progression.
Most notable of these are the last two, Gold and Platinum chunks. Gold Chunks are worth 3,000 Gald a pop, while Platinum Chunks are worth even more at 5,000 Gald each. These items exist purely to sell with no other uses, so that's another plus. You won't be left wanting for these later after selling them.
You can sell all of the materials that you get that you may not want for some extra Gald on top of your commodities.
Mining points take in-game time to respawn, so we recommend clearing out a handful of areas in a loop. Gilanne Woodlands, Iglia Wastes, Lavtu Marshlands, Razum Quarry, Shinefall Woods, and Traslida Highway are all areas that we found to be good for farming mining spots, but other areas may feel better or faster for you.
Fish that aren't tasty sell well
Fish take a good bit longer to get than rocks do, but if you need a break from endless mining, it's not bad. Even cheap fish can sell for upwards of 500-600 Gald and pricier fish can sell for several times that much.
Be careful about which fish you choose to farm, though. Some fish are cooking ingredients and sell for rock-bottom prices. These ones are few and far between, but keep an eye out for when a fish you reel in is counted as an ingredient and not a commodity.
For help setting up your fishing empire in Tales of Arise, go check out How to fish in Tales of Arise? on Pro Game Guides!