I have recently found issue in which Font toolbar was missing after server migration.
- Check following settings on Blog site
- Go to "Post > List settings"
- Under "Columns" option you will get "Body column" which is "Multiple lines of text"
- Click on Body name, it will show you "Body column's settings"
- Under "Additional column settings" find for "Specify the type of text to allow"
- Right now it must be with "Plain text" so change it to "Enhanced Rich Text" which will give you toolbar back.
"Enhanced Rich Text" option is enabled by default