Healing draughts and gonne shells both had their vendor values nerfed a while back, presumably to discourage crafters from endlessly churning out low-cost, high-value crafts to peddle while not interacting with the player economy. However, there remain a few outlier products that are still flagrant examples of goods that can be manufactured cheaply and quickly while having a high sales value to NPC merchants. These include:
Acid Bombs
Fire Bombs
Spell Components
In particular, these are examples of products where the appraised sale value of these goods is considerably higher than what players are typically willing to pay - the average market value of spell components is around 550-600gp, for example, but you can easily get over 700gp from a peddler with them when you have a decent appraisal score. As a result, you're typically losing money selling them to other players compared to your alternatives. Plenty of people still sell them below peddler values, of course, because they want to be involved in the player economy - but it would be nice to not risk someone buying out entire stacks just to peddle them.
As a result, I'd suggest reducing their vendor values to be more in-line with how much healing draughts are now worth.