Nameplate Classification Tag
You can use the tags across all elements that can use tags within ElvUI
Available Tags List / Info
Simply installing the addon will add and register the custom tags with ElvUI and you can view them right in-game via the "Available Tag" window (shows tag name, usage, and examples were applicable)
Nameplate Absorb Tag
Another instance of using absorb tag on nameplate to show the absorb amount of the mob you are killing (for purges, etc)
Classification Icon Tag
Shows classification icon tag (think of the gold/silver dragon emblems). But now shows different icons for different mob types (boss, elite-plus, elites, rares, and rare elites). Icon is sized dynamically via tag (see tag info for details).
Boss Health Tag
Showing simple boss health percentage using a custom tag where you can dynamically change the number of decimals within the tag. Also, the show's "elite-plus" classification icon.
Status Tag
Will show afk, dnd, offline, ghost, and dead tags with custom icons for each
Collage
Raid Group Number
As a raider, I always had to open up my raid tab to see what group I was in for mechanics/assignments. Now you can simply see using a tag next to your name. I use the tag on my player frame (it will only show in raid)
Absorb Tag
Showing absorb amount in parenthesis @ player frame