On Windows, I use uBlock Origin + SponsorBlock + fuckfuckadblock + Enhancer for YouTube (which adds many features such as granular custom speed up to 14x and the ability to still sort by oldest first).
Others have suggested the Brave browser, as well as AdNauseam, a powerful and fascinating browser extension which invisibly clicks every ad you're served without actually showing them to you, thus confusing cookie trackers.
On Android, I use ReVanced Extended. To open YouTube links in ReVanced instead of the default app, long press on the default YouTube app, hit the info button, and disable the app, then long press on ReVanced, open its info page, and check all four URLs under "open by default."
iOS users can use uYou+.
There's also SmartTubeNext for Android TVs, and you can look into personal networkwide adblocking with a Pi-hole or AdGuard.
Using a VPN to get YouTube Premium very cheaply from a country such as India or Turkey is another option (unlocks the higher bitrate of YouTube Music, premium bitrate 1080p videos, and YouTube Premium originals).
To enhance your Reddit experience, there's the Reddit Enhancement Suite for desktop and various Android and iOS apps (including a modified version of Apollo!) which will continue working after the API access lockdown.
I also use archive.ph and Sci-Hub to bypass article paywalls (and Breakthrough Twitter Login Wall), Night Owl for global darkmode, this dark theme for qBittorrent (and here are some other themes), and NordVPN for jumping geofences (I know their ads are a meme and that they're not the best for privacy, but they have a huge range of IP addresses for geounblocking against which the smaller, more privacy-conscious VPNs can't compete; a two-year standard plan for about $3.50 a month plus cashback through Rakuten is the best deal). You should also know that binding your torrent client to your VPN service is more secure than a killswitch.
For downloading videos, I use AnyStream Plus, StreamFab (expensive but crackable), the Internet Downloader Manager, JDownloader2, and kannagi0303's gui for yt-dlp + The Stream Detector (filter for "master"). If you're comfortable with mostly CLI tools or none of the aforementioned GUI tools work on a particular site or video, u/TPD94's CDM-Project has various tools such as vinetrimmer, and you can ask for help on their Discord. If all else fails, you can use a screenrecorder like OBS or Audials.
I also just installed DeArrow (from the developer of SponsorBlock), which crowdsources replacements for clickbait titles and thumbnails, and I'm currently researching virtual credit card services for purchase protection, anonymity, and the ability to buy digital content that's restricted to other regions.
Other tools I use include MakeMKV + a LibreDrive for 4K Blu-ray ripping, a 1TB seedbox from ultra.cc for five euros a month + FileZilla to FTP from it, and 1TB free cloud storage from TeraBox (very slow downloads on the free tier and no guarantee of data retention, so use it only for noncritical data).
r/DHExchange, r/lostmedia, r/oldbritishtelly, and r/tv_bunny are great for finding obscure shows and movies, r/Soulseek is great for music, and the Audiobook Bay for
Came across your post this was really helpful, The adguard one was particularly more helpful to block those annoying ass on tv.