At first I thought there were only 80/88 Uncommon cards possible to unlock in the LOTR card set also but I figured it out and found the missing 8 "Uncommon" LOTR cards. Filter on "Not Collected" LOTR cards and you will find that there are (8) Nazgul cards grouped together under one Nazgul card. Hit the little left-right arrow on the Nazgul card to expand the group and you will then see all 8 Nazgul horse riders. I unlocked all 8 Nazgul cards and the total count of 88 was reached. This seems like a bug since the 8 Nazgul cards don't show up in the list of Uncommon cards however they are visible when filtering on "Not Collected" LOTR cards.
At first I thought there were only 80/88 Uncommon cards possible to unlock in the LOTR card set also but I figured it out and found the missing 8 "Uncommon" LOTR cards. Filter on "Not Collected" LOTR cards and you will find that there are (8) Nazgul cards grouped together under one Nazgul card. Hit the little left-right arrow on the Nazgul card to expand the group and you will then see all 8 Nazgul horse riders. I unlocked all 8 Nazgul cards and the total count of 88 was reached. This seems like a bug since the 8 Nazgul cards don't show up in the list of Uncommon cards however they are visible when filtering on "Not Collected" LOTR cards.