Adverbs starting with the letter Y are listed here. Many kinds of adverbs are included which can be useful for creating interesting sentences.
yea, yeah, yearly, yearningly, yehhh, yes, yesterday, yet.
yon, yonder, youthfully.
There are lots of other useful posts on Adverb1.com to explore which are similar to the above Y adverbs list but which start with different letters for example.