Account Items in Monster Hunter World are specially gathered for the accumulation of Research Points. They serve no functional purpose during hunts aside from rewarding high Research Points, and most unlock a new Canteen ingredient when gathered for the first time. These items do not show up in your Item Pouch, but once picked up can be found in the menu during an outing, under Research Points > Account Items/Endemic Life. The Upsurge/Flourishing can occur in low, high, and master ranks, so it helps to check all three when looking at Locale Info on the map.
The Geologist skill is highly useful, as it allows for an extra item from gathering points and mining outcrops.
Account Items in MHW