Point YouTube links to Invidious, Twitter to Nitter, Instagram to Bibliogram, Reddit to Teddit, Medium to Scribe
For a little more privacy: rewrite YouTube links to point to your favorite Invidious instance. Details on the „why" can be found here.
If you are using the Mouseover Popup Image Viewer (MPIV), here's an example rule for the preview image:
{"r":"(invidious\\.snopyta\\.org/watch.+?v=|v/)([a-z0-9_-]+)", "s":"https://invidious.snopyta.org/vi/$2/mqdefault.jpg"}
Additionally, since version 1.1.0 (2019-09-05) also rewrites Twitter links to Nitter.Net – and starting with v1.2.6 (2020-03-14) also Instagram links to Bibliogram. Since v1.5.0 (2020-11-28) Reddit links can be rewritten to a Teddit instance, v1.6.0 added Medium to Scribe. Reasoning is the same – and Nitter is to Twitter what Invidio.us is to YouTube, etc.
If you don't like the pre-configured one, you can simply change it via the UserScript menu. A list of instances can be found in the Invidious Wiki, another one at instances.invidio.us. Similarly, the Nitter project has a list in its wiki, as does Bibliogram. The userscript menu offers to open those pages in a new tab, next to the one you currently have focused.
If you don't want links for a given service to be rewritten, just set the corresponding instance to an empty string (possible since v1.5.1).