New social media platforms come and go - and change in popularity - all the time. The best way to find out about new platforms is often on existing platforms. For instance, an artist may tweet about content they have just added to a new platform.
Equally, people you already follow are often the best source of leads to new people to follow. A blogger of interest to you will probably link to other relevant blogs.
Alternatives to X (Twitter) are discussed in this article from November 2022.
Mastodon is discussed in this article, which lists many resources for making the most of this platform.
Pinterest is a huge website, mainly for sharing images found online. Pinterest is best-known for consumer products, but is so big that the amount of art-related content is still very large.
Different platforms are popular in different countries. For instance, Weibo, often described as the Chinese-language X (Twitter), is important in China.