Currently, I'm looking for things that I could make and sell to make a lot of grass. Is there anything other than map art that y'all could recommend?
I would agree with NS that farming quartz and shulkers are worth it. They are the most dangerous, but probably make you the most profit in time spent. When I started I would grind quartz and farm gold to sell. This also gives xp which you can use to enchant diamond picks with silk touch and sell for pretty decent profit for someone starting out. Wood is also really good. It doesn’t sell for as much for time spent, but people are always buying it. You want to sell something people will always buy if it’s priced right. Hope this helps.
Anything considered "ores" always sell, voter keys, shulkers, trading can be highly profitable, and rares/mini rares if you know some collectors.
What I recommend if you don't have much yet is that you start off grinding gold at public farms like IllegalFries and sell for 15-18:1 (if you need a sword GucciShop sells iron swords for 1 grass). Once you've made around 102 grass (the price of a full set of diamond armor and a diamond sword) I recommend spending that on full diamond armor and a diamond sword and grinding shulkers at /warp hostile and selling those are 1:1-2 grass (with the full set of diamond armor you can also travel safely through the nether and grind quartz and raid fortresses). I spent most of my early skyblock days grinding shulkers and after I got a good sum of grass I got into buying/selling any high demand item I could get my hands on like redstone dust/blocks, gold, iron, diamonds, voter keys, and mini rares like hunt heads, beacons, nether stars, and eventually elytras, creeper heads, wither skulls, and other mid-high rares like dp heads or geggs, deggs, and dheads. This was the route I've taken to get where I'm at today and not to brag but I'd say I'm pretty successful. The grind is long and hard but in my opinion its very much worth it. Goodluck (if you have any questions feel free to msg me in game my IGN is OmarsCraft)