A lot of novels have huge lists of tags, so it's easy to miss some of the more disturbing tags. It'd be nice, I think, if tags such as r-18, rape, abuse, etc. were coloured red or something to differentiate them and make them stand out from the normal tags.
To expand on the feature, please also have a color for tags that are up the reader's alley. So red for tags they don't like and green for ones they do (or smth), so I can easily fulfill my incest kink (don't shame me)
To be honest, I'd much rather see something like tag sections that'd separate tags based on what they were referring to. For example: World/Main Settings: Cultivation, Multiple Realms, Reincarnation Main Leads: Charismatic Protagonist, Cunning Protagonist, Ruthless Protagonist Cultivation System: Alchemy, Body Tempering, Dao Comprehension, Demons, Heavenly Tribulation, Pill Concocting Romance: Romantic Subplot, Unrequited Love R-18: ... You get the idea. Sections would disappear if there were no tags belonging to them in a series. ~~ Alternatively, something like mangaupdates has - tag voting where users can choose the tags they think are most important and only a certain number with most votes will be displayed by default and the rest will be hidden under a link. The current tag oceans on the series page can be rather confusing.
Runsing has wanted this since forever, but it's hard to implement, so it's been on the backlog for a long time now. An option to allow users to color code certain tags might be much easier to implement though~