Customizing your web browser experience can be done easily with extensions. I personally use Google Chrome and find certain extensions to be very useful when trying to focus and steer clear of content I may find unhelpful.
uBlock Origin blocks content that is often intrusive to your web experience. Ads, tracking, malicious URLs, and more are blocked, offering more privacy protection and generally saving you from plagues of ads.
CleanView by ActiveFence allows you to blur and grayscale visual content, set up whitelist/blacklist sites and also includes wellness break reminders for taking a break from your screen. This has become one of my favorite extensions and I would've loved to have found it earlier!
Advanced Profanity Filter
Advanced Profanity Filter is pretty self-explanatory and very customizable. This extension allows you to remove or replace profanity/curses on your web pages. It can even filter out profanity in videos so long as captions are available for it to detect profane language.
Block YouTube Feed
Block YouTube Feed does what it says! This extension suffices for completely removing the YouTube feed, so your first look at YouTube wouldn't be endless browsing but rather your sidebar and searchbox.
My Blocker Extensions
I have some very simple extensions (that may or may not work) you may try out for yourself or send pull requests to improve them:
There are plenty more extensions that are useful for productivity, but these are a few that I've found very useful for my needs. Let me know what extensions you like to use!