There are few drop in replacements. Some you might have to replace with several apps or change the way you do certain tasks.

Instagram, X, LinkedIn, and Facebook are hard to replace. Their value comes mainly from the network of the people on there.

You might be able to move communication in a friend group to a Signal group chat.

Pixelfed and Mastodon can replace them partially as well. It really depends on the audience though. If you want to connect with tech folk, mastodon can be great, if you want fashionistas, less so.

Anything using lots of video uses lots of expensive bandwidth, so the free replacements usually suffer in this category. There’s no good endless scrolling reels replacement available at the moment.

PeerTube exists for video, but it’s pretty bare bones and lacks the huge community YouTube has.

Amazon does a million things from shopping, video streaming, backend services. There are alternatives to all of these.

Media subscription services for music and video don’t have good replacements. You can go with piracy and host your own Netflix using jellyfin. Spotify is from Sweden, IIRC.

Google Drive, Dropbox, and other file hosting on the cloud have lots of alternatives, that will lack one feature or another. OpenCloud and NextCloud are the biggest names, but any hoster that gives you WebDAV can replace it partially. It also depends on your use case: cloud backup, sharing files, accessing files across devices, working on the same file, etc.