since there are not many uniques that are worth bigmoney then there are very limited options what items are worth shitload
if you ignore bossing then your only options are raw currency + rares + bases + few magic items for example emerald jewel that increase quiver efficiency ones those can sell up to 20-30 div~
rares are kinda tricky since you need to know what is even worth picking up + price checking all of em is time consuming if you don't know instantly whats worth selling
but yeah most of my wealth recently has been from selling rare items, currently I got rare items listed for 400~ divs
for quick price checking this is decent
https://github.com/Sidekick-Poe/Sidekick
if you are not getting many rares or currency then you are probably running shit maps, rare monsters + quantity + rarity and some delirium (ideally paranoia but greed is fine too if you got low magic find)
for map events breach + ritual are obviously the best ones, you can sell audience for like 8 div now