There is a texture mod that will show up as one of the most endorsed. There are several graphics mods. Some just change the colors, others are a complete overhaul. I use the one with the 'gritty' settings. You can use one that just tones down the yellow for a less flashy pallet, or a Fantasy look, and others.
I have about 30-35 mods running now. Though I'm turning off auto apply oils and realistic potions because they get on my nerves. There is a complete overhaul called Witcher Enhanced, but they still improving it, so I just used The Enhancement System. It overhauls battle mechanics, spells, Gwent, etc. I recommend these:
- Signs overhaul
- More Horses
- Leave Roach Alone
- Gear Improvements Last Longer
- No item level requirements
- Better Icons
- Lore-Friendly Witchers (makes Geralt paler with brighter eyes, as he should look)
- Always Full Exp
- Auto-Loot
- High-Quality Faces
- More Shadows
- Fast Travel from anywhere
- All quest objectives on map
- Over 9000 weight limit
- The Witcher 3D Reworked Project
- Better Trophies
- Script Merger
- E3FX graphics overhaul
- The texture one...forgot the name
The ones in bold I'd consider essential for immersion, or, like in auto loot's case, convenience. There's others like the texture one that don't show up in mod manager because I did them manually, so I'm forgetting a few of them.