Formal:
* Anthology: A collection of writings by various authors, often on a particular theme.
* Miscellany: A collection of diverse writings, including poems.
* Compilation: A collection of materials gathered from various sources, including poems.
* Folio: A collection of sheets of paper bound together, which could contain poems.
* Volume: A book containing a collection of poems, often by a single author.
Less Formal:
* Book of poems
* Poetry collection
* Verse collection
* Lyric collection
* Poetry anthology
More Creative:
* Songbook (for a collection of poems that are more lyrical or song-like)
* Versefolio (a blend of "verse" and "folio")
The best word to use depends on the specific collection of poems and the context in which you are using it.