I've been thinking about this. Maybe you could have the traveling merchants having their homes there, in Back-log Village, and there they sell you something extra like
Cutemon: a blue apple pie that idk works on dungeons and let's you gain some +% of exp maybe
Floramon: maybe some sort of unique decoration or a bouquet of flower that is a weapon that inflicts love/sleep/paralisis randomly
Monmon: idk I would just like to have his data (he's my favorite) but maybe a booster that works in the dungeons?
Compassmon: maybe an item that serves like the map skill wo having it.
Lalamon: I have nothing. Maybe some sort of cannon that let's you bust the status inflicting pilars.
Wormmon: maybe a rainbow cloak that gives +% to everykind.
And maybe a Dopemon that sells you pastiles directly so you could make those and then go to Supplemon and make vitamins.
That's all I've been thinking. Is really fun to do so while playing. Really appreciate your work and love the game.
P.S: maybe you could fix the inventory arrows so they can turbo add the number of items to sell? At least in the android version you gotta add them one by one and it takes forever to sell 99 items.