I came across boldlytype.com today when trying to figure out how to format part of a mastodon post as quoted text. It doesn’t seem to be possible to do any formatting directly in mastodon. It does work when a post from discourse is federated to mastodon, and is quite pretty! See example below:
boldlytype.com is cool in that it helps to overcome limitations of just about every publishing platform, including mastodon, by converting text to unicode (examples: 𝘔𝘢𝘬𝘦 𝘺𝘰𝘶𝘳 𝘸𝘰𝘳𝘥𝘴 𝘣𝘰𝘭𝘥𝘭𝘺 𝘺𝘰𝘶𝘳𝘴. 𝕸𝖆𝖐𝖊 𝖞𝖔𝖚𝖗 𝖜𝖔𝖗𝖉𝖘 𝖇𝖔𝖑𝖉𝖑𝖞 𝖞𝖔𝖚𝖗𝖘.˙sɹnoʎ ʎlploq spɹoʍ ɹnoʎ ǝʞɐW). This makes text that is formatted differently easy to copy/paste to anywhere.
This is not great for accessibility so should be used sparingly!