TL;DR: add the ability to associate icons with Account and Merchant entities, ideally resolving them automatically.
Coming from other apps, Lunch Money feels very text-heavy rather than visual, almost like reading an old-school printout (the monospace font contributes to this). You can work around this slightly by adding emojis to category names (though I think categories deserve a dedicated icon field, too), but emojis don't work for accounts and merchants, which are the other core entities.
I would love to see icon support added to their settings. The minimum requirement would be the ability to manually upload an icon (typically a favicon). A nice-to-have would be automatic resolution: this should be easy for synced accounts, and could be a best-effort for manual accounts and merchants (adding a "website" field to merchants would allow automatic fetching too).
For lots of folks, this would make it much faster to assess transaction tables, but also Net Worth, account overview, etc.
PS: I understand Merchant is a new terminology for Payee, but this is quite confusing for new users. I think this should be called out in the Merchant page, while you hopefully converge.