Those are rookie numbers. Need to start getting entire TV shows in 4k and things you've seen previously but may want to watch again in the future quickly and easily.
Personally can't justify many series in 4k, some of the ones I have only ever got SD releases (DVD at best) but there are a few I can justify 4K for. Mainly very cinematic shows such as The Mandelorian or The Last of Us. As long as they have subtitles in the other shows and are available in their best original release resolution it's fine for me.
For example if the original Doctor Who series had a 4K release for it's entirety it would probably be my entire server lol. 693 episodes in 480p is almost 300GB.
It's probably the entire database of World Cup matches (including qualifier matches), plus the entire database of entries to the Eurovision Song Contest (including those of national finals), in addition to every single thing that happened at the 'Lympic Games. All in glorious 8K quality (yes, everything got upscaled by world class upscaling software).
It started as a classic Disney film collection and has expanded quite dramatically over the last 7ish years.
Now a days I've got a half a dozen users feeding requests into Ombi along with a bunch of imdb lists being monitored; growing the library entirely automatically.
/edit: who am I kidding, it's just hundreds of copies of one man one jar with different filters applied...