I have 84 whelp crests and only 77 drake crests (I haven’t done any upgrades except first one). I didn’t even do the campaign. I have no idea how you could miss getting whelp crests if you are looting chests, killing rares and doing the quests. I have no real idea what they come from but you usually do everything and I skip lots…
Whelpling’s Dreaming Crests Regular and world quests, Amirdrassil on the Raid Finder difficulty, and Mythic+ dungeons up to level +5
Drake’s Dreaming Crests Elite quests, Amirdrassil on the Normal difficulty, and Mythic+ dungeons from level +6 to +10
Actually if you want the Whelping Crests just go do the world quests in the Zaralek Caverns. I have been getting 4 for each quests I have done. If you don’t get them there then blizzard is giving them based on ilvl maybe - this character is ilvl 425 I am getting them on.
Also Drake Crests can be obtained from the Brimming Supply Packs from the original factions - got 4 from completing the extra rep quest.