I looked around regarding read more tags and it seems they only work with posts. Is that true?
I have some text fields on my front page where I would like to use Read more tags with a link to another part of the homepage.
As to what I found out that wont work because those text fields are no posts.
Yes, read more tags are only available for posts when excerpts are enabled. However, if you want to add read more tag in the Text block, you can simply use a Button element and link it to the part within your homepage using its ID. You can add ID to any element in the page under ID field of its settings (see: http://prntscr.com/7qep0j).