no spoilers] I tried to make some Arcane gifs under 10Mo with a size close to 600x240px, to eventually use them on your Discord banner. Should i do some more ? :
Rick Roll - Animated Discord Banner
Halloween-banner GIFs - Get the best GIF on GIPHY
Opgif ruffy monkey d ruffy GIF auf GIFER - von Doridar
Vapor Banner(Commission) by nobu_michi -- Fur Affinity [dot] net
Top 30 Discord Banner GIFs | Find the best GIF on Gfycat
too's Animated Beatmap Banner · forum | osu!
Top 30 Discord Banner GIFs | Find the best GIF on Gfycat