For me, the best Skyrim mods transform the realm's aesthetics. Be that by way of weather overhauls, lighting ENBs, or, my newest favourite, BuzzDee84 and PhenomFazMFQ's Ultimate HD Fire Effects SSE.
I've a particular fondness of the dark arts in high-fantasy RPGs, and the College of Winterhold is always my first stop during new playthroughs of Skyrim. As always, the best way to show off mods of this calibre is with pictures.
Courtesy of the project's Nexus Mod page, here's a collection of before and after shots, magic spells in motion, and conjured Atronachs for your pleasure:
Ultimate HD Fire Effects SSE is more than an update of its Oldrim counterpart, with a host of nips and tucks—including improved smoke patterns, over 20 new textures, several meshes and 4K-8K resolution support.
Fancy that? More information on Ultimate HD Fire Effects SSE, including installation instructions, lives on its Nexus Mods page.